Q. Which of the following hormone secreted from anterior pituitary has direct action on body rather than having action on any other gland?
Solution:
The pituitary gland is attached to the hypothalamus by a stalk and located in a bony cavity called sella tursica. It is divided into an adenohypophysis (with pars distalis, pars tuberalis, and pars intermedia) and neurohypophysis. The pars distalis region of the pituitary produces the following hormones:
Growth hormone (GH): The growth hormone has a direct action on body, causing elongation of bones of limbs. Over-secretion of GH stimulates abnormal growth of the body leading to gigantism in children while acromegaly in adults. and low secretion of GH results in pituitary dwarfism.
Prolactin (PRL): Prolactin regulates the growth of the mammary glands and the formation of milk in them.
Thyroid-stimulating hormone (TSH): TSH stimulates the synthesis and secretion of thyroid hormones from the thyroid gland.
Adrenocorticotrophic hormone (ACTH): ACTH stimulates the synthesis and secretion of glucocorticoids from the adrenal cortex.
Luteinizing hormone (LH): LH and FSH stimulate gonadal activity and hence are called gonadotrophins. In males, LH stimulates the interstitial cells or Leydig’s cells for synthesis and secretion of hormones called androgens (testosterone) from the testis. In females, LH induces ovulation of fully mature follicles (Graafian follicles) and maintains the corpus luteum, a yellow coloured body formed from the remnants of the Graafian follicles after ovulation.
Follicle-stimulating hormone (FSH):- FSH is also known as gametokinetic factor or gametogenesis. In males, FSH and androgens regulate spermatogenesis. FSH stimulates the growth and development of the ovarian follicles in females.
Pars intermedia secretes only one hormone called MSH. MSH acts on the melanocytes and regulates pigmentation of the skin. Excess release of melanin leads to a reduction in vitamin D synthesis in the body which may lead to osteomalacia.
Growth hormone (GH): The growth hormone has a direct action on body, causing elongation of bones of limbs. Over-secretion of GH stimulates abnormal growth of the body leading to gigantism in children while acromegaly in adults. and low secretion of GH results in pituitary dwarfism.
Prolactin (PRL): Prolactin regulates the growth of the mammary glands and the formation of milk in them.
Thyroid-stimulating hormone (TSH): TSH stimulates the synthesis and secretion of thyroid hormones from the thyroid gland.
Luteinizing hormone (LH): LH and FSH stimulate gonadal activity and hence are called gonadotrophins. In males, LH stimulates the interstitial cells or Leydig’s cells for synthesis and secretion of hormones called androgens (testosterone) from the testis. In females, LH induces ovulation of fully mature follicles (Graafian follicles) and maintains the corpus luteum, a yellow coloured body formed from the remnants of the Graafian follicles after ovulation.
Follicle-stimulating hormone (FSH):- FSH is also known as gametokinetic factor or gametogenesis. In males, FSH and androgens regulate spermatogenesis. FSH stimulates the growth and development of the ovarian follicles in females.
Pars intermedia secretes only one hormone called MSH. MSH acts on the melanocytes and regulates pigmentation of the skin. Excess release of melanin leads to a reduction in vitamin D synthesis in the body which may lead to osteomalacia.