What is the endocrine system? How does it work? Explore the key components of this vital system and discover its crucial role in regulating mood, growth, development, and more.

Understanding the Endocrine System

The endocrine system is a complex network of glands that produce and secrete hormones, the body’s chemical messengers. These hormones play a crucial role in controlling and coordinating various bodily functions, from metabolism and growth to mood and reproduction.

The Glands of the Endocrine System

The major glands that make up the endocrine system include the hypothalamus, pituitary, thyroid, parathyroids, adrenal glands, pineal body, ovaries, and testes. Each of these glands produces specific hormones that have a unique impact on the body’s processes.

Hypothalamus

The hypothalamus is a small but powerful region in the lower central part of the brain. It acts as a link between the endocrine system and the nervous system, sending signals to the pituitary gland to regulate the release of hormones.

Pituitary Gland

Often referred to as the “master gland,” the pituitary gland is located at the base of the brain and is no bigger than a pea. It produces a variety of hormones that control other endocrine glands, including growth hormone, prolactin, and hormones that regulate the reproductive system.

Thyroid Gland

The thyroid gland, situated in the front of the lower neck, produces hormones that control the rate of metabolism, the process by which the body converts food into energy. These hormones play a crucial role in regulating growth and development, especially in children and adolescents.

Parathyroid Glands

The four tiny parathyroid glands, located behind the thyroid, release a hormone that helps maintain the proper balance of calcium in the blood and bones.

Adrenal Glands

The adrenal glands, situated atop the kidneys, have two distinct parts: the adrenal cortex, which produces hormones that help regulate salt and water balance, the body’s stress response, and sexual development, and the adrenal medulla, which produces hormones like adrenaline that increase heart rate and blood pressure during times of stress.

Pancreas

The pancreas is a unique gland that is part of both the endocrine and digestive systems. It produces hormones like insulin and glucagon that regulate blood sugar levels, as well as enzymes that aid in the digestion of food.

The Role of Hormones

Hormones are the chemical messengers that allow the endocrine system to influence almost every cell, organ, and function of the body. They are responsible for regulating mood, growth and development, metabolism, and reproduction, among other crucial processes.

Hormone Production and Regulation

Endocrine glands release hormones directly into the bloodstream, allowing them to travel to target cells and tissues throughout the body. The endocrine system carefully regulates the production and release of hormones, with levels often dependent on factors like hormone concentrations already present in the blood or other substances.

Hormone Imbalances

Too much or too little of any hormone can have harmful effects on the body. Fortunately, many hormone-related conditions can be treated with medications that help restore the proper balance.

The Endocrine System and the Nervous System

The endocrine system and the nervous system work in close collaboration to coordinate the body’s responses to various stimuli. The hypothalamus serves as a key link, receiving information from the brain and sending signals to the pituitary gland to regulate hormone production.

The Endocrine System and Overall Health

The endocrine system plays a vital role in maintaining overall health and well-being. By producing and regulating hormones, it influences a wide range of bodily functions, from growth and development to mood and metabolism. Understanding the endocrine system is crucial for recognizing and addressing any potential hormonal imbalances or conditions.

Conclusion

The endocrine system is a complex and intricate network of glands and hormones that is essential for the proper functioning of the human body. By regulating mood, growth, development, metabolism, and reproduction, this system plays a crucial role in maintaining overall health and well-being. Understanding the key components of the endocrine system and how it works is essential for recognizing and addressing any potential hormonal imbalances or conditions.

Endocrine System (for Parents) – Nemours KidsHealth

What Is the Endocrine System?

The endocrine system is made up of glands that make hormones. Hormones are the body’s chemical messengers. They carry information and instructions from one set of cells to another.

The endocrine (EN-duh-krin) system influences almost every cell, organ, and function of our bodies.

What Does the Endocrine System Do?

• Endocrine glands release
  hormonesinto the bloodstream. This lets the hormones travel to cells in other parts of the body.
• The endocrine hormones help control mood, growth and development, the way our organs work,
  metabolism, and reproduction.
• The endocrine system regulates how much of each hormone is released. This can depend on levels of hormones already in the blood, or on levels of other substances in the blood, like calcium. Many things affect hormone levels, such as stress, infection, and changes in the balance of fluid and minerals in blood.

Too much or too little of any hormone can harm the body. Medicines can treat many of these problems.

What Are the Parts of the Endocrine System?

While many parts of the body make hormones, the major glands that make up the endocrine system are the:

• hypothalamus
• pituitary
• thyroid
• parathyroids
• adrenals
• pineal body
• the ovaries
• the testes

The pancreas is part of the endocrine system and the digestive system. That’s because it secretes hormones into the bloodstream, and makes and secretes enzymes into the digestive tract.

Hypothalamus: The hypothalamus (hi-po-THAL-uh-mus) is in the lower central part of the brain. It links the endocrine system and nervous system. Nerve cells in the hypothalamus make chemicals that control the release of hormones secreted from the pituitary gland. The hypothalamus gathers information sensed by the brain (such as the surrounding temperature, light exposure, and feelings) and sends it to the pituitary. This information influences the hormones that the pituitary makes and releases.

Pituitary: The pituitary (puh-TOO-uh-ter-ee) gland is at the base of the brain, and is no bigger than a pea. Despite its small size, the pituitary is often called the “master gland.” The hormones it makes control many other endocrine glands.

The pituitary gland makes many hormones, such as:

• growth hormone, which stimulates the growth of bone and other body tissues and plays a role in the body’s handling of nutrients and minerals
• prolactin (pro-LAK-tin), which activates milk production in women who are breastfeeding
• thyrotropin (thy-ruh-TRO-pin), which stimulates the thyroid gland to make thyroid hormones
• corticotropin (kor-tih-ko-TRO-pin), which stimulates the adrenal gland to make certain hormones
• antidiuretic (an-ty-dy-uh-REH-tik) hormone, which helps control body water balance through its effect on the kidneys
• oxytocin (ahk-see-TOE-sin), which triggers the contractions of the uterus that happen during labor

The pituitary also secretes endorphins (en-DOR-fins), chemicals that act on the nervous system and reduce feelings of pain. The pituitary also secretes hormones that signal the reproductive organs to make sex hormones. The pituitary gland also controls
ovulationand the menstrual cycle in women.

Thyroid: The thyroid (THY-royd) is in the front part of the lower neck. It’s shaped like a bow tie or butterfly. It makes the thyroid hormones thyroxine (thy-RAHK-sin) and triiodothyronine (try-eye-oh-doe-THY-ruh-neen). These hormones control the rate at which cells burn fuels from food to make energy. The more thyroid hormone there is in the bloodstream, the faster chemical reactions happen in the body.

Thyroid hormones are important because they help kids’ and teens’ bones grow and develop, and they also play a role in the development of the brain and nervous system.

Parathyroids: Attached to the thyroid are four tiny glands that work together called the parathyroids (par-uh-THY-roydz). They release parathyroid hormone, which controls the level of calcium in the blood with the help of calcitonin (kal-suh-TOE-nin), which the thyroid makes.

Adrenal Glands: These two triangular adrenal (uh-DREE-nul) glands sit on top of each kidney. The adrenal glands have two parts, each of which makes a set of hormones and has a different function:

1. The outer part is the adrenal cortex. It makes hormones called corticosteroids (kor-tih-ko-STER-oydz) that help control salt and water balance in the body, the body’s response to stress, metabolism, the immune system, and sexual development and function.
2. The inner part is the adrenal medulla (muh-DUH-luh). It makes catecholamines (kah-tuh-KO-luh-meenz), such as epinephrine (eh-puh-NEH-frun). Also called adrenaline, epinephrine increases blood pressure and heart rate when the body is under stress.

Pineal: The pineal (pih-NEE-ul) body, also called the pineal gland, is in the middle of the brain. It secretes melatonin (meh-luh-TOE-nin), a hormone that may help regulate when we sleep at night and wake in the morning.

Reproductive Glands: The gonads are the main source of sex hormones. In boys the male gonads, or testes (TES-teez), are in the scrotum. They secrete hormones called androgens (AN-druh-junz), the most important of which is
testosterone(tess-TOSS-tuh-rone). These hormones tell a boy’s body when it’s time to make the changes associated with puberty, like penis and height growth, deepening voice, and growth in facial and pubic hair. Working with hormones from the pituitary gland, testosterone also tells a boy’s body when it’s time to make sperm in the testes.

A girl’s gonads, the ovaries (OH-vuh-reez), are in her pelvis. They make eggs and secrete the female hormones
estrogen(ESS-truh-jen) and
progesterone(pro-JESS-tuh-rone). Estrogen is involved when a girl starts puberty. During puberty, a girl will have breast growth, start to accumulate body fat around the hips and thighs, and have a growth spurt. Estrogen and progesterone are also involved in the regulation of a girl’s menstrual cycle. These hormones also play a role in pregnancy.

Pancreas: The pancreas (PAN-kree-us) makes insulin (IN-suh-lin) and glucagon (GLOO-kuh-gawn), which are hormones that control the level of glucose, or sugar, in the blood. Insulin helps keep the body supplied with stores of energy. The body uses this stored energy for exercise and activity, and it also helps organs work as they should.

What Can Help Keep the Endocrine System Healthy?

To help keep your child’s endocrine system healthy:

• Get plenty of exercise.
• Eat a nutritious diet.
• Go for regular medical checkups.
• Talk to the doctor before taking any supplements or herbal treatments.
• Let the doctor know about any family history of endocrine problems, such as diabetes or thyroid problems.

When Should I Call the Doctor?

Let the doctor know if your child:

• drinks a lot of water but is still thirsty
• has to pee often
• has frequent belly pain or nausea
• is very tired or weak
• is gaining or losing a lot of weight
• has tremors or sweats a lot
• is constipated
• isn’t growing or developing as expected

Reviewed by: Larissa Hirsch, MD

Date reviewed: October 2018

Brain Hormones | Endocrine Society

The pituitary gland and the hypothalamus—are located in or near the brain. The hypothalamus and the pituitary gland are like orchestra conductors. Their job is to tell other endocrine glands throughout the body to make the hormones that affect and protect every aspect of your health. Found deep inside the brain, the hypothalamus produces releasing and inhibiting hormones and controls the “master gland”— the pituitary. Together, the hypothalamus and pituitary tell the other endocrine glands in your body to make the hormones that affect and protect every aspect of your health.

Pineal glands is important for the sleep cycle regulation of female reproductive hormone associated with fertility and menstrual cycle. Researchers are still learning about the potential functions of the pineal gland and the hormone melatonin. Other hormones produced in the brain are:

• Antidiuretic Hormone (ADH) – also called vasopressin, which regulate sodium levels and water balance. Lack of ADH causes increased urination and thirst, a condition that is called diabetes insipidus.
• Thyrotropin-releasing hormone (TSH) is produced in the hypothalamus and stimulates the release stimulates the thyroid gland to produce thyroid hormones. Too much TSH is rare and will cause hyperthyroidism (too much thyroid hormone). Lack of TSH results in hypothyroidism (not enough thyroid hormone). 

Hypothalamus Hormones

Kisspeptin, made in the hypothalamus, is an important hormone that starts the release of several other hormones. Also called metastin, this interesting hormone is connected to puberty and may also help stop the spread of cancer.

What Does Kisspeptin Do?

Kisspeptin enters into receptor sites in the pituitary gland, starting a reaction that causes the gland to release neurotransmitters. Those neurotransmitters then signal the release of luteinizing hormone and follicle stimulating hormone. These hormones have a role to play in the production of testosterone and oestradiol. Without kisspeptin, this entire chain reaction would be damaged.

Kisspeptin has a secondary function that is not related to hormones. Its original name, metastin, points to its ability to prevent the spread of cancer in the body.Kisspeptin is released in conjunction with two other hormones: dynorphin and neurokinin B. These two hormones are not understood well, but early research indicates they may have a role in causing the release of kisspeptin.

Potential Problems with Kisspeptin Levels

Having high levels of kisspeptin is not related to any conditions or symptoms, although preliminary research indicates that high kisspeptin levels in childhood can lead to early puberty, but this has not yet been proven. Research has also found that women have high levels of kisspeptin in their blood streams during pregnancy, but why this occurs is not yet understood.

Improper kisspeptin function or low kisspeptin levels, however, can cause problems. Specifically, inadequate function of this hormone can cause infertility by preventing menstruation in women. Sometimes, just one injection of kisspeptin can trigger ovulation, which can allow for artificial insemination and in vitro fertilization using the woman’s eggs.

In adolescents, low kisspeptin levels or poor kisspeptin signaling can delay or prevent the onset of puberty. Other problems connected to high or low kisspeptin levels are still being discovered and researched.

If you are struggling with fertility, kisspeptins may be one of the reasons. Talk to your healthcare provider about your kisspeptin levels, and learn whether kisspeptin treatment could potentially help.

Oxytocin is a hormone produced by the hypothalamus and secreted by the pituitary gland. This important hormone plays a crucial role in the childbirth process and also helps with male reproduction. Understanding oxytocin will help you take better care of your health and lead you toward a better understanding of how your body functions.

In women, oxytocin is responsible for signaling contractions of the womb during labor. The hormone stimulates the uterine muscles to contract, so labor begins. It also increases the production of prostaglandins, which move labor along and increases the contractions even more. Because of this effect, synthetic oxytocin (pitocin) is sometimes used to induce a woman to start labor if she cannot start naturally, or it can be given to make contractions stronger if a woman’s labor is slowing.

Once the baby is born, oxytocin promotes lactation by moving the milk into the breast. When the baby sucks at the mother’s breast, oxytocin secretion causes the milk to release so the baby can feed. At the same time, oxytocin is released into the brain to stimulate further oxytocin production. Once the baby stops feeding, the production of the hormone stops until the next feeding.

For men, oxytocin function is less important, but it does have a role to play in moving sperm. It also appears to affect the production of testosterone in the testes.

Studies of oxytocin also have found that it is an important chemical messenger that controls some human behaviors and social interaction. It is oxytocin that triggers the bond between a mother and an infant, and it may also play a role in recognition, sexual arousal, trust, and anxiety. Some research shows that the hormone may affect addiction and stress as well.

How is Oxytocin Production Controlled?

Oxytocin production is controlled by a positive feedback mechanism. This mechanism allows the release of the oxytocin hormone when a trigger occurs. The hormone then causes an action in the body, such as the letdown of milk or the start of labor contractions, which signals more production of oxytocin. The feedback cycle continues until the action, such as childbirth or feeding the baby, is complete.

Problems with Oxytocin Production

High and low oxytocin levels are possible, but research has not yet found any implications of these conditions. Men with high levels of oxytocin sometimes develop benign prostatic hyperplasia, or the enlarging of the prostate gland. This condition can cause urinary complaints. A lack of oxytocin can prevent the milk letdown reflex and make breastfeeding difficult. Low oxytocin levels have also been linked to depression, but using oxytocin to treat mental health conditions has not yet been studied sufficiently.

If you have further questions about oxytocin, or simply want to ensure that your hormones are functioning properly, you need the services of an endocrinologist.

Gonadotrophin-releasing hormone (GnRH) is produced from cells in the hypothalamus. It is then released into small blood vessels that carry the hormone to the pituitary gland. As a consequence, the pituitary gland produces luteinizing hormone (LH) and follicle-stimulating (FSH) hormones. These hormones, LH and FSH, are essential to male and female reproductive health. GnRH causes the pituitary gland to secrete LH and FSH.

In childhood, GnRH levels are low. As puberty begins, GnRH levels start to rise. When the testes and ovaries are fully developed, GnRH, LH, and FSH production are controlled by the levels of testosterone and female sex hormones (estrogen and progesterone). In women, FSH encourages eggs to grow in the ovaries. Leading to the production of estrogen, which signals to the pituitary gland to decrease the release of FSH and to produce more LH, causing ovulation and FSH and LH levels to drop. In men, GnRH stimulates the production of LH from the pituitary gland. LH attaches to receptor cells in the testes, which starts the production of sperm cells.

What Problems Can Occur with GnRH?

Research is still being conducted on the effects of having too much GnRH. In rare cases, pituitary tumors can develop, which increases the production of gonadotropins (LH and FSH), which might cause the body to overproduce testosterone and estrogen. If GnRH levels are too low, it often means that a person does not begin puberty. Kallmann’s Syndrome is an condition where gonadotropin levels are low due to inadequate GnRH levels. This condition is more common among men and is accompanied by a decreased sense of smell. Also, damage to the hypothalamus can halt GnRH production. This will also stop the regular production of FSH and LH. This may lead to amenorrhea in women, loss of sperm production in men, and loss of hormones made from the ovaries or testes.

Pineal Hormones

Melatonin is created by the pineal gland in the brain. In a healthy, normally functioning individual, melatonin is released in a rhythmic cycle, with more melatonin produced at night when the light entering the eyes starts to diminish. The bloodstream carries it to the different areas of the body, where receptors pick up the melatonin to signal the need for sleep. 

Melatonin is essential to signaling the relaxation and lower body temperature that help with restful sleep. Levels of melatonin are higher at night, signaling the body that it is time to rest. In animals, the hormone also regulates seasonal biology, such as the reproductive system, winter coat growth, and hibernation behaviors. A connection between melatonin and human reproduction or seasonal cycles has not yet been established. Because it is so connected to sleep, melatonin has been called the “sleep hormone.” However, it is not necessary for sleep, and people can sleep with inadequate levels of melatonin in the body. That said, the secretion of melatonin does allow individuals to sleep better.

Problems Connected with Melatonin

People do not experience problems with melatonin secreted naturally by the body. The amount of melatonin produced by the body, whether low or high, is not associated with any health problems. In fact, in a lifetime, melatonin levels increase and decrease during the various stages of life. Low levels of melatonin do not appear to have any serious effects on health — although it can make sleep difficult to achieve if the levels change.

However, melatonin supplementation as a sleep aid is popular, and sometimes people will take too much melatonin. This can cause drowsiness and a reduced core body temperature. Extremely high levels of melatonin can also contribute to headaches and fatigue. It’s also possible for very large doses of melatonin to affect human reproduction.

If you are considering taking melatonin supplements to help with sleep, consider asking your healthcare provider:

• How much melatonin do I need?
• How much melatonin is too much?
• How long can I take melatonin safely?
• Is long-term melatonin use dangerous?

How Does the Body Uses Serotonin?

Mood: Serotonin is in the brain. It is thought to regulate mood, happiness, and anxiety. Low levels of serotonin are linked to depression, while increased levels of the hormone may decrease arousal.

Bowel Movements: Serotonin is found in your stomach and intestines. It helps control your bowel movements and function.

Nausea: Serotonin is produced when you become nauseated. Production of serotonin increases to help remove bad food or other substances from the body. It also increases in the blood, which stimulates the part of the brain that controls nausea.

Sleep: Serotonin is responsible for stimulating the parts of the brain that control sleep and waking. Whether you sleep or wake depends on the area is stimulated and which serotonin receptor is used.

Blood Clotting: Serotonin is released to help heal wounds. Serotonin triggers tiny arteries to narrow, which helps forms blood clots.

Bone Health: Having very high levels of serotonin in the bones can lead to osteoporosis, which makes the bones weaker.

Mental Health: Serotonin helps regulate your mood naturally. When your serotonin levels are at a normal level, you should feel more focused, emotionally stable, happier, and calmer.

What Problems are Associated with Low Levels of Serotonin?

Low levels of serotonin are often associated with many behavioral and emotional disorders. Studies have shown that low levels of serotonin can lead to depression, anxiety, suicidal behavior, and obsessive-compulsive disorder. If you are experiencing any of these thoughts or feelings, consult a health care professional immediately. The sooner treatment starts, the faster you’ll see improvements.

What Problems are Associated with High Levels of Serotonin?

Serotonin syndrome can occur when you take medications that increase serotonin action leading to side effects. Too much serotonin can cause mild symptoms such as shivering, heavy sweating, confusion, restlessness, headaches, high blood pressure, twitching muscles, and diarrhea. More severe symptoms include high fever, unconsciousness, seizures, or irregular heartbeat. Serotonin syndrome can happen to anyone, but some people may be at higher risk. You are at a higher risk if you increased the dose of medication that is known to raise serotonin levels or take more than one drug known to increase serotonin. You may also be at risk if you take herbal supplements or an illicit drug known to increase serotonin levels.

If you suspect that your serotonin levels are too high or low, the first step is to speak with a health care professional.

Consider asking your doctor:

• Is my medication causing serotonin syndrome?
• If I am experiencing feelings of depression, are my serotonin levels too low?
• Are my levels of serotonin affecting any other aspects of my health?

Pituitary Hormones

Adrenocorticotropic hormone (ACTH) plays a large role in how your body responds to stress. ACTH is produced in the pituitary gland, its production stimulates the production and release of cortisol from the adrenal gland. After ACTH is made in the pituitary gland, ACTH is released into the bloodstream and travels around the body. Production of ACTH is regulated by corticotrophin-releasing hormone (CRH) from the hypothalamus and cortisol from the adrenal gland. If ACTH levels are low, the hypothalamus releases CRH which is key to the stress hormone system and acts on many areas of the brain such as appetite and memory. Once the CRH is discharged, it triggers the pituitary gland to secrete ACTH.

High levels of ACTH are detected by the adrenal gland, which starts the production of cortisol. When cortisol levels rise in the body, the brain can sense these high levels and the production of the CRH and ACTH decreases. Stress activates ACTH production and increases cortisol levels.

What Problem Can Occur With ACTH?

If too much ACTH is produced, this can lead to high levels of cortisol in the body, also known as Cushing syndrome. The most common cause of increased ACTH production is a benign pituitary tumor.  When this is present, the disorder is called Cushing disease. Other endocrine conditions that may lead to an increase of ACTH include adrenal insufficiency and congenital adrenal hyperplasia.

Having lower than normal ACTH levels in the blood can be a result of other endocrine conditions such as Cushing syndrome or hypopituitarism. 

ACTH Testing
To diagnose these conditions, healthcare providers can order an ACTH blood test. An ACTH test is ordered if a cortisol blood test has abnormal results or if a patient has symptoms of too much or too little cortisol. Analyzing ACTH and cortisol levels together can help identify the different endocrine conditions associated with high and low cortisol levels. To test ACTH levels, healthcare providers may require you to fast overnight and conduct the test early in the morning. This is because ACTH levels are high in the morning and gradually decrease during the day. ACTH is at its lowest level during sleep. 

Human growth hormone (GH) is a substance that controls your body’s growth. GH is made by the pituitary gland, located at the base of the brain. GH helps children grow taller (also called linear growth), increases muscle mass, and decreases body fat. In both children and adults, GH also helps control the body’s metabolism—the process by which cells change food into energy and make other substances that the body needs.

If children or adults have too much or too little GH, they may have health problems. Growth hormone deficiency (too little GH) and some other health problems can be treated with synthetic (manufactured) GH. Sometimes GH is used illegally for non-medical purposes.

How is Growth Hormone Therapy Used?

The U.S. Food and Drug Administration (FDA) has approved GH treatment for certain conditions. GH is available only by prescription and is injected. Synthetic GH seems to be safe and effective when used as prescribed for the FDA-approved conditions.

In children, GH is used to treat:

Growth hormone deficiency
Conditions that cause short stature (being shorter than children of the same age), such as chronic kidney disease, Turner syndrome, and Prader-Willi syndrome

In adults, GH is used to treat:

Growth hormone deficiency
Muscle wasting (loss of muscle tissue) from HIV
Short bowel syndrome

GROWTH HORMONE SOLD WITHOUT A PRESCRIPTION
Some companies sell human GH pills or GH releasers, claiming that the pills are “anti-aging” substances. But these substances have not been proven to increase the body’s production of GH or to fight aging, increase muscle, or provide other benefits. GH has no effect if it is taken as a pill because it is inactivated (loses its action) during digestion.

In addition to these uses, doctors outside and a number within the U.S. sometimes prescribe GH for other health problems. (When doctors prescribe medicines for conditions other than the ones officially approved, the process is called “off-label” use.)

If you’re worried about GH deficiency in yourself or a family member, talk with a doctor.

Is Growth Hormone Use Appropriate for Healthy Adults?

Studies of healthy adults taking GH have produced conflicting results. Some short-term studies showed that older adults increased their endurance and strength, with increased muscle and decreased fat mass. But other studies did not show similar benefits. More studies are needed to fully understand the benefits and risks of GH use in healthy adults.

Aside from its use in research studies, prescribing or using GH off-label is illegal in the US. Adults can achieve improved health, body composition, strength, and endurance by following a healthy diet and getting frequent exercise.

How is Growth Hormone Abused?

People sometimes take GH illegally to stop or reverse the effects of aging or to improve athletic performance. Some athletes believe taking GH alone will not achieve the desired results, so they take it along with anabolic (tissue building) steroids in an effort to build muscle, increase strength, and decrease body fat. Some athletes also use insulin to increase the muscular effects of GH, which is a dangerous practice because it lowers blood sugar.

What Are the Risks of Growth Hormone Abuse?

People can experience harmful side effects when they abuse GH. Side effects of short-term use include joint and muscle pain, fluid build-up, and swelling in the joints. If GH is injected with shared needles, people may be exposed to HIV, AIDS, or hepatitis. Taking high doses of GH over a long time may contribute to heart disease.

GH sold illegally may contain unknown and potentially harmful ingredients. For instance, if people take GH derived from human tissue, they risk developing a fatal brain disease called Creutzfeldt-Jakob disease, which is similar to mad cow disease. Consider asking your healthcare provider:

• Do I (or my child) need human growth hormone treatment for medical reasons?

• What are the benefits and risks of growth hormone treatment?

• What are the signs of growth hormone abuse?

• Should I see an endocrinologist about my condition?

Human Chorionic Gonadotropin (hCG) hormone is important in the early stages of pregnancy. It is produced by cells that are surrounding a growing embryo, which eventually forms the placenta. hCG can be detected in your body as early as 1 week after an egg is fertilized, which forms the basis of most over the counter pregnancy tests. hCG also ensures the corpus luteum, a temporary endocrine gland a woman’s body produces after ovulation, continues to produce progesterone during the first trimester of pregnancy. Low concentrations of hCG  are also produced by the pituitary gland, thus, men and non-pregnant women still have detectable levels of HcG throughout their lives.

The levels of hCG increases every two to three days as your embryo continues to develop. hCG levels peak around the sixth week of pregnancy. Afterwards, hCG will be found in your body, but the levels will begin to decrease. Once the placenta is fully formed, it serves as a source of progesterone production and assistance from hCG to support ovarian function is no longer essential.

What Problems can Occur with hCG?

Very high hCG levels are rare. In these cases, it may be sign of a molar pregnancy, which is an abnormal growth of cells that usually develop in the placenta. In people who are not pregnant, high hCG levels may be due to certain cancers such as breast, kidney, and lung. Low levels of hCG may be a sign of a miscarriage or another problem within the pregnancy, such as the embryo implanting outside of the uterus. Consider asking your healthcare provider:

• How early can doctors detect my hCG levels?

• What test is the best way to detect pregnancy?

• Why is hCG important in the early stages of my pregnancy?

Luteinizing hormone (LH) is produced and released in the anterior pituitary gland. This hormone is considered a gonadotrophic hormone because of its role in controlling the function of ovaries in females and testes in males, which are known as the gonads.

In women, the hormone stimulates the ovaries to produce oestradiol. Two weeks into a woman’s cycle, a surge in luteinizing hormone causes the ovaries to release an egg during ovulation. If fertilization occurs, luteinizing hormone will stimulate the corpus luteum, which produces progesterone to sustain the pregnancy.

For men, luteinizing hormone stimulates the production of testosterone from Leydig cells in the testes. Testosterone, in turn, stimulates sperm production and helps accentuate male characteristics — like a deep voice or growth of facial hair.

What Problems Can Occur With Luteinizing Hormone?

People who have high levels of luteinizing hormone may experience infertility, because the hormone directly impacts the reproductive system. In women, luteinizing hormone levels that are too high are often connected to polycystic ovary syndrome, which creates inappropriate testosterone levels. Some genetic conditions, like Turner syndrome or Klinefelter syndrome, can cause high levels of the hormone, as well. People with these conditions are often unable to reproduce.

Low levels of luteinizing hormone can also cause infertility, because insufficient levels will limit the production of sperm or the ovulation process. Too little luteinizing hormone stops ovulation in women or creates a deficiency in gonadotrophin-releasing hormone (GnRH) secretion in men.

If you are struggling with infertility or other reproductive-system complaints, poor luteinizing hormone levels. Consider your healthcare provider:

• What hormone imbalances could be affecting my fertility?

• What blood tests should I have to determine the hormones that are not in proper balance?

• Is there any way to treat these imbalances?

• How can I support a better hormone balance naturally?

Prolactin, as its name implies, is a hormone that promotes lactation (breast milk production) in mammals and is responsible for a number of other functions and systems. Prolactin is created in the front portion of the pituitary gland in your brain, as well as in the uterus, brain, breasts, prostate, adipose tissue, skin, and immune cells.

Prolactin (also known as luteotropin) function is still being studied, but research seems to show a variety of purposes for this hormone. For instance, it also regulates behavior, the immune system, metabolism, reproductive systems, and many different bodily fluids. This makes it a crucial hormone for overall health and well-being, for both men and women. Production of prolactin is controlled by two main hormones: dopamine and estrogen. These hormones send a message to the pituitary gland primarily indicating whether to begin or cease the production of prolactin. Dopamine restrains the production of prolactin, while estrogen increases it.

Possible Problems with Prolactin Production

For most people, prolactin does its job without a problem, and few are aware of the impact it has on their health. Yet some people can struggle with prolactin levels, which can cause a variety of problems. Too much prolactin in the blood causes hyperprolactinemia, a condition that can lead to menstrual disturbances, estrogen deficiency and testosterone deficiency. High prolactin levels also can cause unwanted lactation. This often occurs during pregnancy or when the thyroid is not functioning properly. Pituitary tumors, known as prolactinomas, and medications that reduce dopamine can also lead to increased prolactin levels. High levels of prolactin are linked to sexual problems. Some of these conditions can be treated with medications that mimic the action of dopamine.

It’s also possible to have too little prolactin, a condition known as hypoprolactinaemia. This is extremely rare, but it can occur if people have under-active pituitary glands. This is commonly noticed in women after pregnancy who are not able to produce sufficient milk. No other proven health effects of low prolactin levels have been noted. Research is underway to determine if those with low prolactin levels suffer from a reduction in immune system responses.

Prolactin is an important, yet not often well-known, hormone. Take control of your health by understanding your hormones and how they affect you. If you are concerned about prolactin levels or functions, consider asking your healthcare provider:

• Is prolactin affecting my ability to produce milk?

• How can I raise or lower my prolactin levels?

• What concerns are there surrounding prolactin?

• How can I monitor prolactin levels?

Return to Hormones and Endocrine Function>>>

What are hormones – different types and their functions

Hormones are chemical messengers in the body that help regulate various processes in the body. There are many different hormones, and each of them performs a specific job.

What are hormones?

The brain, pituitary, thyroid, or adrenal glands can produce hormones. Through the bloodstream, they enter various parts of the body, interacting with cells, tissues and organs. Hormones affect many bodily functions such as growth, metabolism, mood, and reproduction. According to the chemical composition, hormones can be divided into three categories: steroid hormones, peptide hormones, and amino acid derivatives.

Steroid hormones

Steroid hormones derived from cholesterol include sex hormones such as estrogen, progesterone, and testosterone, as well as adrenal cortex hormones, including cortisol, aldosterone, and androgens. Steroid hormones are transported throughout the body in the bloodstream by transport proteins.

Peptide hormones

Peptide or protein hormones include pituitary hormones, growth hormone, prolactin, LH and FSH, thyroid hormones (T3 and T4), insulin, glucagon and PTH. Peptide hormones are rapidly degraded, allowing organisms to efficiently use them to control processes without a long signal.

Endocrine system and endocrine glands

The endocrine system consists of many organs called glands that produce hormones. Hormones then act as chemical messengers to coordinate many bodily functions. The main endocrine glands are the pituitary, thyroid and adrenal glands, which are part of the endocrine system. The hormones produced by these glands help regulate critical bodily functions, including growth, metabolism, and the response to stress.

Pituitary gland

The pituitary gland is located at the base of the brain. It is often referred to as the “master gland” because it produces hormones that regulate the production of hormones by other glands. The pituitary gland is controlled primarily by the hypothalamus, which detects the level of hormones in the body and signals the pituitary gland to secrete hormones that increase or decrease the hormone production of the target glands. The pituitary gland consists of two parts: the anterior and posterior lobes. The anterior pituitary gland produces six hormones: growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin. The posterior pituitary gland produces only two hormones: vasopressin and oxytocin.

Growth hormone

Growth hormone (hCG), also known as growth hormone, is responsible for bone and muscle growth and cell reproduction. It is involved in the regulation of bone and muscle growth and energy metabolism. Growth hormone plays an important role in increasing height during puberty and maintaining bone strength in adulthood.

Thyroid Stimulating Hormone

Thyroid Stimulating Hormone (TSH) regulates the functioning of the thyroid gland. The thyroid gland produces hormones that regulate metabolism, heart rate, and body temperature. Thyroid-stimulating hormone tries to ensure the correct levels of thyroid hormones in your body. Too high thyroid hormone levels can cause hyperthyroidism, and too low thyroid hormone levels can cause hypothyroidism.

Adrenocorticotropic hormone

Adrenocorticotropic hormone (ACTH) regulates the adrenal glands. The adrenal glands produce hormones involved in the stress response, metabolism, and blood pressure regulation. ACTH regulates the production of the adrenal hormone cortisol, the stress hormone. Abnormal levels of cortisol can negatively affect the body and indicate other diseases such as Cushing’s syndrome.

Follicle stimulating hormone

Follicle stimulating hormone (FSH) is an important hormone for the reproductive organs. FSH regulates the functioning of the ovaries in women and testicles in men. In particular, FSH is involved in the development of eggs in women and sperm in men.

Luteinizing Hormone

Luteinizing Hormone (LH) is another hormone involved in the reproductive system that regulates the ovaries in women and the testicles in men. LH is involved in ovulation (the release of an egg from the ovary) in women and testosterone production in men.

Prolactin

Prolactin is involved in milk production and development of the mammary glands.

Vasopressin (antidiuretic hormone)

Vasopressin, also known as antidiuretic hormone (ADH), regulates the body’s water balance by regulating the excretion of water by the kidneys. For example, vasopressin helps the body retain water by reducing urine output.

Oxytocin

Oxytocin is involved in reproduction, lactation and bonding. It is sometimes referred to as the “hug hormone” because oxytocin is released during hugs and other forms of physical contact.

Thyroid gland

The thyroid gland is located in the neck. It produces two hormones: thyroxine (T4) and triiodothyronine (T3). These hormones help regulate metabolism, heart rate, and body temperature.

Adrenals

The adrenal glands sit above the kidneys and produce hormones involved in the body’s response to stress, metabolism and blood pressure regulation. The adrenal glands are composed of two parts: the adrenal cortex and the adrenal medulla oblongata. The adrenal cortex produces three main hormones: glucocorticoids, mineralocorticoids, and androgens. The adrenal medulla produces two hormones: epinephrine and norepinephrine. All of these hormones are involved in the body’s “fight or flight” response.

Glucocorticoids

Glucocorticoids are involved in the stress response, regulation of the immune system and metabolism. The most important glucocorticoid is cortisol, the main stress hormone in the body.

Mineralocorticoids

Mineralocorticoids are involved in electrolyte balance and blood pressure regulation. The most important mineralocorticoid is aldosterone, which controls sodium and potassium levels in the body.

Androgens

Androgens are male sex hormones. The most important androgen is testosterone, which regulates the development of the male reproductive system and plays a role in the development of muscle and bone mass. Androgens may also be present in small amounts in women.

Epinephrine

Epinephrine, also known as adrenaline, prepares the body for the flight or fright response during times of acute stress. It increases heart rate, blood pressure, cardiac output and increases glucose levels.

Norepinephrine

Norepinephrine is considered a neurotransmitter and hormone. Norepinephrine is also released in response to acute stress and affects many organs and tissues in the body. This includes dilating the pupils, opening the airways, and increasing the heart rate.

Ovaries

The ovaries are located in the pelvic area. They produce two main hormones: estrogen and progesterone. Estrogen is involved in the development of female sexual characteristics and the regulation of the menstrual cycle. Progesterone is involved in preparing the uterus for pregnancy.

Testes

The testicles are located in the scrotum and produce two main hormones: testosterone and inhibin. Testosterone is involved in the development of male sexual characteristics, such as muscle and hair development, and in sperm production. Inhibin is involved in the regulation of sperm production.

Pancreas

The pancreas is located in the abdomen and produces hormones that help regulate blood sugar levels, including insulin, glucagon, and somatostatin. These hormones help regulate blood sugar levels. The pancreas releases insulin to lower blood sugar levels and releases glucagon to raise blood sugar levels. Somatostatin inhibits the release of glucagon and insulin.

Parathyroid gland

The parathyroid gland is located behind the thyroid gland. It produces a hormone called parathyroid hormone (PTH), which regulates calcium levels in the blood, which is essential for maintaining healthy bones.

Pineal gland

The pineal gland is located in the brain and produces the hormone melatonin. Melatonin helps regulate the sleep-wake cycle and the body’s natural circadian rhythm.

Hormone imbalance

A hormonal imbalance occurs when there is too little or too much of one or more hormones. Too high or too low levels of certain hormones can have a noticeable effect on the body. Hormone imbalances can lead to diabetes, infertility, thyroid disease, and obesity. Several natural processes in the body can change hormone levels, including puberty, menopause, and pregnancy.

Other factors that can cause abnormal changes in hormone levels include high levels of stress, environmental exposure, lifestyle including diet and exercise, or medication. Some natural ways to keep your hormone levels normal include eating a balanced diet with enough protein, exercising regularly, finding ways to reduce stress like meditation or yoga, and maintaining a healthy body weight.

Frequently Asked Questions: What are hormones

Which hormone is the most important in the body?

There is no one “most important” hormone in the body. Different hormones are needed to perform different functions. For example, thyroid hormones help regulate metabolism, while adrenal hormones help regulate the stress response.

What are the symptoms of a hormonal imbalance?

Hormonal imbalance symptoms can vary depending on which hormones are out of balance. For example, an imbalance in thyroid hormones can cause fatigue, weight gain, or depression. An imbalance of sex hormones can cause irregular periods, hot flashes, or decreased libido. If you experience any unusual symptoms, you should see your doctor to determine if a possible hormone imbalance is causing these symptoms. Laboratory tests can help identify hormone imbalances.

What is the difference between a hormone and a neurotransmitter?

Hormones are chemicals that help the body control its growth and function. Hormones are chemicals produced by the glands. Through the blood, they enter various parts of the body. A neurotransmitter is a chemical that helps relay messages between nerve cells in the nervous system.

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Hormones: What they are, functions and types

18.1 Types of Hormones – Biology Concepts – 1st Canadian Edition

Endocrine System: What it is, Functions and Organs

Pituitary Overview – Hormonal and Metabolic Disorders – Merck Manuals Consumer Version

Reactome | Glycoprotein hormones

Pancreas | Johns Hopkins Medicine

Epinephrine | Description, production and functions | Britannica

Norepinephrine: What it is, functions, deficiency and side effects.

HGH (Human Growth Hormone): What it is, Benefits and Side Effects

What is TSH?

Adrenocorticotropic Hormone (ACTH): MedlinePlus Medical Test

Cortisol: What it does and how to regulate cortisol levels

Aldosterone | You and Your Hormones from the Society of Endocrinology

10 Natural Ways to Balance Your Hormones

Hormonal Imbalance: Causes, Symptoms and Treatment

Sex Hormones

• Progesterone 902 78
• Testosterone
• Prolactin
• Luteinizing hormone (LH)
• Follicle stimulating hormone (FSH)
• Human chorionic gonadotropin (hCG)
• Free B-hCG
• Estradiol
• Androstenedione

Reproductive function in both sexes is completely controlled and regulated by hormones. The main sex hormones are divided into two classes – estrogens (female) and androgens (male). Both men and women have both types of hormones, but in completely different amounts. So, for example, the daily production of the male hormone testosterone in men is 20-30 times greater than in most women. In turn, the female sex hormone estradiol is also found in small amounts in men. In women, in addition to the two main classes of hormones, there is another class: gestagens, the main representative of this class is progesterone. In men, sex hormones are formed in the tissue of the testicles, in women they are synthesized by the ovaries, in addition, regardless of gender, a small amount of hormones is produced in the adrenal cortex. It is believed that estrogens are more responsible for memory, and androgens are responsible for cognitive functions, mood, and sexual desire. Excess and, conversely, deficiency of hormones equally adversely affect health. So, deficiency and excess of testosterone prevent the maturation of the egg.

Progesterone – The main function is to prepare a woman’s body for pregnancy. It is necessary to maintain pregnancy and tone the smooth muscles of the uterus. Prevents excessive growth of the uterine mucosa and affects the tissue of the mammary glands (stimulates the growth and development of the glandular tissue of the mammary glands, helps prepare them for lactation).

Every month, estrogen causes the inner lining of the uterus, the endometrium, to grow and renew itself, while luteinizing hormone (LH) releases an egg in one of the ovaries. In place of the released egg, the so-called corpus luteum is formed, which produces progesterone. Progesterone, along with a hormone secreted by the adrenal glands, stops the growth of the endometrium and prepares the uterus for the eventual implantation of a fertilized egg. If fertilization does not occur, the corpus luteum disappears, progesterone levels fall and menstrual bleeding occurs. If the fertilized egg attaches to the wall of the uterus, the corpus luteum continues to produce progesterone. After a few weeks, the placenta takes over the function of the corpus luteum to produce progesterone, being the main source of this hormone during pregnancy.

The test is used to identify causes of infertility, diagnose ectopic or pathological pregnancies, monitor the condition of the fetus and placenta during pregnancy, and determine if the patient has ovulated.

Testosterone is the main male sex hormone responsible for the formation of secondary sexual characteristics and sexual function. Its synthesis is stimulated and controlled by luteinizing hormone (LH) produced by the pituitary gland. Testosterone levels fluctuate significantly throughout the day, reaching their peak between 4 and 8 am, and the minimum occurs in the evening hours (between 4 and 8 pm).

In addition, its concentration increases after exercise and decreases with age. In especially large quantities, it is produced in adolescents during puberty. In men, testosterone is synthesized by the testicles and adrenal glands, and in women, by the adrenal glands and, to a small extent, by the ovaries .

Testosterone promotes the development of secondary sexual characteristics such as penis enlargement, body hair growth, muscle development and a deep voice. In adult males, it regulates sexual instincts and the maintenance of muscle mass. Testosterone is also present in a woman’s body, although at a lower concentration. Libido (sexual desire), the ability to orgasm, insulin levels, a slim figure, the development of muscle mass, and bone tissue depend on it. Testosterone is responsible for the activity and tolerance of emotional stress. In postmenopause, when estrogens and gestagens disappear, it is testosterone that will maintain bone density, the cardiovascular system for some time and help to endure menopausal syndrome more easily.

The analysis is prescribed for male and female infertility or reduced sexual desire, delayed or premature puberty in boys and erectile dysfunction in men, with diseases of the hypothalamus, pituitary gland, testicular tumors.

Luteinizing hormone (LH) is a hormone of the anterior pituitary gland responsible for the smooth operation of the entire gonadal system, as well as for the production of male and female sex hormones – progesterone and testosterone. In women, LH acts on the cells of the ovary membrane and the corpus luteum, stimulates ovulation and activates the synthesis of estrogens and progesterone in ovarian cells, in men – on testicular cells, activating testosterone synthesis in them, due to which, in particular, maturation occurs spermatozoa .

The analysis is carried out to diagnose infertility and assess the functional state of the reproductive system.

FSH (follicle stimulating hormone) regulates the production of sex hormones, but is not itself such, since it is produced not by the gonads, but by the pituitary gland. In the body, FSH regulates the activity of sex glands : promotes the formation and maturation of germ cells ( eggs and spermatozoa ), affects the synthesis of female sex hormones ( estrogens ).

In women FSH affects the formation of follicles . Reaching the maximum level of FSH leads to ovulation . In men FSH stimulates the growth of seminiferous tubules , increases the level of testosterone in the blood, thereby ensuring the process of maturation of spermatozoa and libido . In men FSH stimulates the growth of seminiferous tubules , increases the level of testosterone in the blood, thereby ensuring the process of maturation of spermatozoa and libido .

Follicle Stimulating Hormone (FSH) levels are used to assess pituitary function, reproductive function (both women and men), and puberty disorders in children and adolescents. The analysis is prescribed to determine the causes of menstrual irregularities of various origins, diagnosis of dysfunctional uterine bleeding, differential diagnosis of central and peripheral forms of diseases of the female reproductive system, monitoring the effectiveness of hormone therapy.

Prolactin is one of the hormones synthesized by the pituitary gland – a gland that controls metabolism, as well as the processes of growth and development of the body. Prolactin is necessary for the normal development of the mammary glands and ensuring lactation – it increases the production of colostrum, promotes its maturation and transformation into mature milk. It also stimulates the growth and development of the mammary glands, an increase in the number of lobules and ducts in them. It also controls the secretion of progesterone and inhibits the production of follicle-stimulating hormone (FLH), ensuring a normal menstrual cycle, inhibiting ovulation and the onset of a new pregnancy. Normally, this physiological mechanism prevents the next child from becoming pregnant while the previous one is breastfeeding, and may prevent menstruation during the nursing period. In the blood of men and non-pregnant women, prolactin is usually present in small amounts. In everyday life, prolactin rises during sleep, exercise and sexual intercourse. But in men, an excessive increase in its level can disrupt sexual function by inhibiting the maturation of sperm in the testicles and causing infertility.

The test is used to diagnose infertility and sexual dysfunction, to study the function of the pituitary gland, to determine the cause of galactorrhea (excretion of milk or colostrum without regard to the process of feeding the child), headaches and visual impairment.

Human Chorionic Gonadotropin ( HCG ) is a hormone that is produced in the fetal membrane of the human embryo. HCG is an important indicator of the development of pregnancy and its deviations. It is produced by the cells of the chorion (the shell of the embryo) immediately after it is attached to the wall of the uterus (this happens only a few days after fertilization). The embryo at this stage of pregnancy is a microscopic vial filled with liquid, the walls of which consist of rapidly multiplying cells. From one part of these cells, the unborn child (embryoblast) develops, while from the cells outside the embryo, a trophoblast is formed – that part of the fetal egg, with which it is attached to the wall of the uterus. Later, the chorion is formed from the trophoblast.

Chorion performs the function of nourishing the embryo, being an intermediary between the body of the mother and the child. In addition, it produces chorionic gonadotropin, which, on the one hand, affects the formation of the child, on the other hand, it specifically affects the mother’s body, ensuring a successful pregnancy. The appearance of this hormone in the body of a future mother at the initial stage of pregnancy explains the importance of the test for early diagnosis of pregnancy.

Chorionic gonadotropin stimulates the secretory function of the corpus luteum of the ovaries, which should produce the hormone progesterone, which maintains the normal state of the inner lining of the uterine wall – the endometrium. The endometrium provides reliable attachment of the fetal egg to the mother’s body and its nutrition with all the necessary substances. Due to a sufficient amount of human chorionic gonadotropin, the corpus luteum, which normally exists for only about 2 weeks during each menstrual cycle, does not undergo resorption upon successful conception and remains functionally active throughout the entire period of pregnancy. Moreover, it is in pregnant women under the influence of chorionic gonadotropin that it produces very large amounts of progesterone. In addition, hCG stimulates the production of estrogens and weak androgens by ovarian cells and promotes the development of the functional activity of the chorion itself, and later the placenta, which is formed as a result of the maturation and growth of the chorionic tissue, improving its own nutrition and increasing the number of chorionic villi.

Thus, the role of human chorionic gonadotropin lies in the specific and multifaceted effect on the body of a woman and the fetus in order to ensure a successful pregnancy.

Based on the analysis of chorionic gonadotropin, the presence of chorionic tissue in the body of a woman is determined, and hence pregnancy. The analysis is used, among other things, for the diagnosis of multiple, ectopic and non-developing pregnancies, the detection of fetal developmental delays, the threat of spontaneous abortion, placental insufficiency. May be prescribed as part of a comprehensive examination to identify fetal malformations, as well as to monitor the effectiveness of artificial abortion.

Free B-hCG – Beta subunit of human chorionic gonadotropin – one of the components of the specific hormone molecule – chorionic gonadotropin, formed in the shell of the human embryo. In the absence of pregnancy, the test result for beta-hCG will be negative. The detection of beta-hCG suggests that at least 5-6 days have passed since fertilization.

The analysis is carried out for the purpose of early diagnosis of pregnancy (3–5 days delay in menstruation), detection of its complications and diagnosis of diseases associated with impaired hCG secretion.

Estradiol is perhaps the main and one of the most active female sex hormones of the estrogen group. It refers to typical female hormones, since, in the female body in a significant amount, it is produced by the ovaries, realizing a large number of physiological functions. In men, estradiol is also produced, but in very small quantities, and has rather auxiliary functions.
In the female body, estradiol plays an extremely important role in the regulation of the menstrual cycle and the functioning of the entire reproductive system. In childhood and puberty, the hormone is responsible for the growth and development of all organs related to the reproductive sphere. Under its influence, cyclic changes occur in the tissues of the genital organs, as well as the formation of secondary female sexual characteristics (growth of the mammary glands, pubic and armpit hair, etc.). In adult women, estradiol stimulates the first phase of the menstrual cycle, causes growth and proliferation (active cell division) of the endometrium, thus preparing it for the introduction of the ovum and the onset of pregnancy. During pregnancy, estradiol increases metabolism in all body tissues. As the pregnancy progresses, it begins to be produced by the placenta in greater and greater quantities, thus providing. increased needs for metabolic rate and blood flow in women. In the male body, estradiol is involved in the formation of sperm, i.e. needed for conception. But, nevertheless, for men, his role is not as significant as for women.

Determination of the level of estradiol in women of childbearing age is carried out in the diagnosis of a large number of diseases and conditions, such as infertility, menstrual irregularities, lack of ovulation, polycystic and ovarian tumors, etc., as well as to assess the functions of the placenta in early pregnancy and monitoring with in vitro fertilization. Used in the diagnosis and treatment of osteoporosis. In men, the analysis is carried out with low sperm quality and infertility, diseases of the adrenal glands and liver.

Androstenedione is the main steroid hormone, it is an intermediate product and the basis for the formation of testosterone and estrone.