Anterior pituitary gland

Hormones of anterior pituitary gland

1. ANTERIOR PITUITARY GLAND & ITS HORMONES Ms.Anu Sebastian: B.Pharm ; M.Pharm Assistant Professor, Dept. Of Pharmacology Nirmala College Of Pharmacy Muvattupuzha,Ernakulam,K

2. ANTERIOR PITUITARY Five types of neurosecretory cells are present in the anterior pituitary.They are: Somatotrophs : It secrete human growth hormone/ somatotropin .It regulate the general body growth & metabolism. Thyrotrophs : It secretes Thyroid stimulating hormone(TSH)/ Thyrotropin . It regulates the synthesis & secretions of thyroid hormones & other activities of thyroid gland.

3. Gonadotrophs : It secrete Follicle-stimulating hormone(FSH ) & leutinizing hormone(LH). It regulate the development of oocyte & sperm and the secretion of estrogen, progesterone & testosterone. Lactotrophs : It secrete prolactin which initiates milk production in the mammary gland. Corticotrophs : It secrete ACTH ( Adrenocorticotropic Hormone)/ Corticotropin . ACTH stimulate the adrenal cortex to secrete Glucocorticoids , mineralocorticoids & Androgen. It also secrete MSH, which stimulate melanocytes to secrete melanin

4. REGULATION OF HORMONAL SECRETION FROM ANTERIOR PITUITARY The secretions of anterior pituitary are regulated by: Releasing & Inhibiting hormones from hypothalamus. Negative feed back Mechanism. GROWTH HORMONE It is secreted by Somatotrophs & it is the most plentiful anterior pituitary hormone. Functions Increases growth rate of skeleton & skeletal muscles during childhood & teenage years. Increases muscle mass & maintain bones.It also promote healing of injuries and tissue repair.

5. Mechanism Human growth hormone Stimulate cells of liver, skeletal muscle ,cartilage Bone Release Insulin like growth factor(IGF) Acts on different body cells in the following way: Increases amino acid uptake by cells which increases protein synthesis. Increases lipolysis for ATP production. Decrease breakdown of proteins & amino acids for ATP production. Decreases glucose uptake which decreases use of glucose for ATP production.

6. Regulation of Release The hormone secretion is regulated by Growth hormone releasing hormone(GHRH) & Growth hormone-Inhibiting hormone(GHIH). Low blood glucose level Stimulate release of GHRH from hypothalamus Stimulate somatotrophs Release human growth hormone hGH stimuate cells to release IGF IGF converts glycogen to glucose Blood glucose level rise to normal

7. THYROID STIMULATING HORMONE/TSH It stimulate the synthesis & release of T3 & T4 from thyroid gland. The secretion of TSH is regulated by Throtropin Releasing Hormone(TRH) from hypothalamus & negative feedback mechanisms. FOLLICLE STIMULATING HORMONE In female FSH initiates the development of ovarian follicles in each month. FSH also stimulate follicle cells to secrete estrogen. In male FSH stimulates sperm production in testes. The secretion of FSH is regulated by Gonadotropin Releasing Hormone/ GnRH from hypothalamus & Negative feed back mechanism.

8. LEUTINIZING HORMONE (LH) In female , LH stimulate ovulation LH stimulate formation of corpus luteum LH stimulate the release of progesterone from corpus luteum . In male, LH stimulate testes to release testosterone The secretion of LH is regulated by Gonadotropin Releasing Hormone/ GnRH from hypothalamus & Negative feed back mechanism. PROLACTIN Along with other hormones like oxytocin , It helps in lactation. The secretion of prolactin is regulated by : PRH( Prolactin -Releasing hormone) PIH( Prolactin -Inhibiting Hormone)

9. ADRENOCORTICOTROPIC HORMONE/ACTH ACTH stimulates the adrenal cortex for the secretion of Glucocorticoids , Mineralocorticoids & androgen. The secretion is regulated by Corticotropin - releasing hormone/CRH from hypothalamus & Negative feedback mechanism. MELANOCYTE STIMULATING HORMONE/MSH MSH stimulate melanoocytes for the secretion of Melanin, which increases the skin pigmentation. The secretion of MSH is regulated by excessive level of Corticotropin - releasing hormone/CRH & secretion is inhibited by Dopamine.

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