Tropic hormones are hormones secreted by the anterior pituitary gland. There are hormones: thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH), luteinizing hormone (LH) and adrenocorticotropic hormone (ACTH). Each of them stimulates the appropriate endocrine organ, and inhibits the hypothalamus (negative feedback), thus reducing the secretion of liberin (hormones that stimulate the pituitary gland to produce and secrete tropic hormones). A deficiency or excess of tropic hormones can lead to all sorts of diseases, including thyroid disease (hypothyroidism or hyperthyroidism), pituitary gland disease, and more.

Contents:

  1. Tropic hormones - thyroid stimulating hormone (TSH)
  2. Tropic Hormones - Follicle Stimulating Hormone (FSH)
  3. Tropic hormones - luteinizing hormone (LH, lutropin)
  4. Tropic hormones - adrenocorticotropic hormone (ACTH)
  5. Tropic hormones - hypopituitarism

Tropic hormonesare hormones secreted by the pituitary gland under the influence of the hypothalamus. The task of tropic hormones is to control the secretion of other hormones that affect the endocrine glands, such as the testes, ovaries, the thyroid gland, and the adrenal cortex.

Tropic hormones - thyroid stimulating hormone (TSH)

Thyroid stimulating hormone (TSH) is a hormone that stimulates the thyroid gland to produce and secrete thyroid hormones, i.e. thyroxine and triiodothyronine (T4 and T3, respectively).

When serum levels of these hormones are low, the pituitary gland increases the secretion of TSH, thereby increasing the release of these hormones into the bloodstream.

There are a number of factors that stimulate the thyroid gland to produce and release hormones, such as cold, the action of certain hormones, such as vasopressin.

In the case of an excess of thyroid hormones in the blood serum, the secretion of TSH from the pituitary gland is inhibited by the mechanism of the so-called negative feedback.

Serum TSH concentration is measured from venous blood. The study does not require any special preparation. The norm is between 0.4 - 4.0 mU / l for an adult. This value is different for children and pregnant women, and for certain thyroid diseases.

In the case of hyperthyroidism, a decreased level of TSH in the serum and increased values ​​of the concentrations of T3 and T4 hormones are observed.

Hypothyroidism is diagnosed in the same way - the level of free hormones is lowered, TSH is above the norm.

Tropic Hormones - Follicle Stimulating Hormone (FSH)

Follicle stimulating hormone (FSH) is a hormone that affects the function of the ovaries. It causes the development and maturation of Graaf's follicles. In women, it supports the production of estradiol and progesterone.

Its concentration increases during ovulation and remains high after the menopause. In men, the level of FSH concentration is constant, it stimulates the production of sperm and proteins that transport sex hormones.

Normal values ​​of FSH concentrations in women depend on the phase of the menstrual cycle. The concentration of the hormone is tested in order to diagnose menstrual disorders, pituitary or ovarian diseases, infertility, and abnormal maturation in children.

The test is usually performed with venous blood (you can also determine the FSH level from a daily urine collection - the test is performed rarely), it does not require preparation.

Tropic hormones - luteinizing hormone (LH, lutropic

Luteinizing hormone (LH, or lutropin), like FSH, affects the function of the ovaries. In women, it stimulates ovulation and stimulates the synthesis of progesterone.

In men, it stimulates testosterone synthesis in the testes.

High levels of testosterone and progesterone in the serum inhibit LH secretion, while GnRH - a hormone produced in the hypothalamus stimulates the secretion of LH from the pituitary gland.

The highest concentration of this hormone is observed in the periovulatory and postmenopausal period, as well as in some diseases, such as polycystic ovary syndrome, Turner syndrome and Klinefelter syndrome, pituitary adenoma, lack of testicles in boys.

Measurement of the concentration of this hormone is performed in the diagnostic mode of menstrual disorders, puberty, and pituitary diseases. The concentration norms in women vary depending on the phase of the menstrual cycle.

Tropic hormones - adrenocortical hormone

Adrenocorticotropic hormone (ACTH) is a hormone that stimulates the adrenal cortex, stimulates the secretion of corticosteroids (to the greatest extent), mineralocorticosteroids and androgens.

ACTH secretion is stimulated by the CRH hormone secreted by the hypothalamus, and inhibited by negative feedback by adrenal hormones.

Glucocorticosteroids are essential for life, too low or too high concentration of these hormones often has dangerous consequences.

Excessive secretion of cortisol, it may occur as a result of, for example, a tumor of the pituitary gland that produces excess ACTH (Cushing's syndrome),less often due to a tumor that secretes ACTH outside the pituitary gland or a tumor of the adrenal gland (secreting cortisol).

Tropic hormones - hypopituitarism

Hypopituitarism manifested by a deficiency of hormones in the anterior pituitary gland poses a serious threat to human he alth and life. This is known as secondary peripheral gland insufficiency. Pituitary insufficiency can be caused by:

  • tumors
  • inflammatory changes
  • head injuries
  • iatrogenic damage e.g. operation
  • congenital disorders
  • haemorrhagic stroke due to postpartum hemorrhage and necrosis in the course of hypovolemic shock - Sheehan's syndrome (postpartum pituitary necrosis)

Category:

He alth