Function of the Pituitary Gland

The essence in brief.

The pituitary gland produces hormones that control other glands in the body. It has two lobes: the front and back lobes. The front lobe hormones regulate growth, cortisol production, milk production, and reproductive processes. The back lobe releases hormones from the hypothalamus into the bloodstream. Hormone levels are regulated through feedback loops. In summary, the pituitary gland is important for hormone control and overall body function.

Stimulated or inhibited by hormones from the hypothalamus, the pituitary gland produces hormones. These hormones control the other endocrine glands in the body. Endocrine glands release hormones into the bloodstream or tissues. The hormones of the front lobe of the pituitary gland act on the thyroid gland, adrenal glands, reproductive organs, mammary glands, and liver. The pituitary gland is divided into two sections: the anterior pituitary lobe and the posterior pituitary lobe. The main hormones of the anterior pituitary lobe are growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), prolactin, luteinizing hormone (LH), and follicle-stimulating hormone (FSH).

Growth hormone stimulates the production of insulin-like growth factors (IGF-1), mainly in the liver. IGF-1 acts on a receptor present on the membranes of almost all cells, thereby promoting growth. The release of growth hormone is inhibited by somatostatin from the hypothalamus.

ACTH stimulates the adrenal glands to produce cortisol, while TSH stimulates the thyroid gland to produce thyroid hormones. Prolactin acts on the mammary glands and promotes milk production. In males, LH stimulates testosterone production in the testes, and in females, it stimulates estrogen production in the ovaries. FSH contributes to sperm production in males and follicle development in females.

The posterior pituitary lobe does not produce hormones itself but is connected to the hypothalamus through a channel system. It releases the hormone ADH (antidiuretic Hormon) produced in the hypothalamus directly into the bloodstream.

The hormone levels in the blood are regulated by feedback loops. If cortisol levels in the blood are too high, it inhibits the release of corticotropin-releasing hormone (CRH) from the hypothalamus and adrenocorticotropic hormone (ACTH) from the pituitary gland. As a result, the adrenal glands ate less stimulated, and cortisol levels decrease. Conversely, if there is too little cortisol in the blood, the production of CRH in the hypothalamus is stimulated. CRH, in turn, stimulates the production of ACTH from the pituitary gland. ACTH promotes the production of cortisol from the adrenal gland. The following are two examples of the regulation of thyroid hormones and cortisol.