Function of hormones of adenohypophysis
Adenohypophysis is the real glandular part of the pituitary gland. The cells adenohypophysis secreted several hormones.
The hormones of adenohypophysis are
1. Somatotrophic hormone(STH):
Growth hormone is secreted by the acidophill cells of the adenohypophysis.
It is polypeptide in nature consisting of large branches.
The molecular weight in human beings is 21500.
The hormone regulates the growth of the body is thus it is necessarily concerned with the growth of skeleton, growth of muscle and growth of other organs.
Function -
It stimulates the growth of skeleton in general by promoting ossification.
Hyper activity of gland in the young increases the growth of skeleton and this condition is known as gigantism.
Hypofunction of gland retrads skeletal growth and produce dwarfism.
The hormones promotes protein anabolism.
The hormone elevates the blood glucose level by stimulating glycogenalysis.
It promotes the release of glucagon from pancreas.
Growth hormone maintains cardiac muscle glycogen.
2. Throid stimulating hormone(TSH):
This hormone is secreted by polyhedral basophill.
It is glucoprotein in nature.
Molecular weight varies from 26000-28000.
Function
This hormone promotes and maintains growth and development of thyroid gland.
It stimulates thyroid gland to secrete its hormone.
In the hypoactive condition, the thyroid is developed when dwarfism may br vaused.
In hyperactive condition, due to excessive secretion acromegaly may br caused.
TSH is concernorl with the uptakr of iodine.
TSH in excess produces degeneration and loss muscle contraction.
3. Adrenocorticotrophic hormone (ACTH):
It is the product of basophill cells.
It is polypeptide in nature consisting of 39 amino acids.
Its molecular weight is 4500 in certain mammals including human.
ACTH secretion is mediated by neurohormonal and feed back mechanism.
Function
ACTH promotes and maintains growth and development of the adrenal cortex.
ACTH has important lypolytic action.
Insulin secretion by the pancreas stimulated.
It plays important role in prolonging the actionbof cortisol.
In case of adrinocortical insufficiency hyper pigmentation can be observed.
4. Follicle stimulating hormone (FSH):
This hormones are secreted by basophill cells.
It is glycoprotein in nature.
FSH has its molecular weight about 17000.
Function
In female FSH increases the weight of ovary and als numbet and size of graffian follicle.
It may induce a little secretion of estrogen.
In male it induces development of seminiferous tubules and also stimulates the process of spermatogenesis, this hormone is called gametokinetic factor.
It has no effect on leydig cells and secretion of androgen.
5. Luteotrophile hormone (LTH)
This hormone is protein in nature and it is secreted by the acidophill cells of the adenohypophysis.
Its molecular weight is 25000.
This hormone is known as lactogenic hormones, the name suggesting that in initiates milk secretion.
Function:
It stimulates the mammary glands for tge secretion of milk after the delivery of child.
It promotes breast development during pregnancy.
It stimulates the proliferation of the glandular elements of mammary glands.
6. Leutinizing Hormone (LH) or (ISCH)
It is protein in nature.
It has molecular weight of 25000.
LH in females and ICSH in males.
Function :
Leutinizing hormone acts with FSH to bring about complete maturation of follicle.
Leutinizing hormone produces ovulation and stimulates the formation of corpus leutium in the ruptured follicles.
It stimulates the corpus leutium to secrete progesterone.
In males it stimulates the secretion of testosterones.
Secretion of androgen helps in the development of seminiferous tubules leading spermatogenesis so, the hormone is known as interstitial cell stimulating hormone (ICSH).
7. Melanocyte stimulating hormone (MSH):
This hormone is polypeptide in nature and is the product of the pars intermedia.
The two form of this hormone have been isolated, they are alpha-MSH and Beta-MSH.
Function :
This hormone stimulates melatonin synthesis in mammalian skin.
MSH causes hyperpigmentation in mammalian skin.
The secretion of MSH is depresed in case of adrenocoxtic sufficiency.
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