Question

The gonadotropic hormone is secreted by
A. Posterior part of thyroid
B. Adrenal cortex
C. Adenohypophysis of pituitary
D. Interstitial cells of testis

Answer 1

These hormones are produced by gonadotropic cells in the anterior lobe of the pituitary gland. They work on the maturation and function of the ovaries and testicles. Gonadotropins are FSH and LH, both of which are glycoproteins. FSH (34 kDa) contains 10% carbohydrate, while LH (25 kDa) contains 15% carbohydrate.

Complete Answer:
- Gonadotropic hormone is secreted by adenohypophysis (anterior pituitary) of the pituitary gland. LH and FSH are collectively referred to as gonadotropin. They are called gonadotropins because they induce gonad activity.
- Follicle Stimulating Hormone (FSH): In males, FSH controls spermatogenesis (sperm formation) and in females, FSH promotes the growth and development of ovarian follicles and the secretion of estrogen hormones.
- Luteinizing Hormone (LH): In males, LH is also called ICSH (Interstitial Cell Stimulating Hormone), which stimulates the testes to synthesize and secrete androgens (testosterone). It stimulates testicular Leydig cells to secrete testosterone. In females, LH promotes the ovulation of completely mature Graafian follicles and also preserves the corpus luteum produced by the remnants of Graafian follicles after ovulation. The corpus luteum secretes progesterone and some estrogen under the influence of LH.

Therefore, option C is the correct answer.

Note: Approximately 50–75% of GnRH neurons express a kisspeptin receptor. Kisspeptin acts primarily at the level of the hypothalamus to stimulate the secretion of GnRH. However, a number of studies have shown the ability of kisspeptins to work directly on pituitary gonadotrope cells to induce LH release.