Assertion: LH acts at the Leydig cells and stimulates synthesis and secretion of androgens.
Reason: Spermatogenesis is initiated during the embryonic development due to significant increase in the secretion of gonadotropin releasing hormone (GnRH).
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Assertion is true and Reason is false.
Spermatogenesis is controlled by hormones. The hypothalamus releases GnRH (gonadotropin releasing hormone). GnRH makes the anterior pituitary release two gonadotropins, LH (luteinising hormone) and FSH (follicle stimulating hormone).
Assertion: LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. — True. Leydig cells lie between the seminiferous tubules. Under LH they make androgens (male hormones), and androgens in turn drive spermatogenesis.
Reason: Spermatogenesis is initiated during the embryonic development due to significant increase in the secretion of gonadotropin releasing hormone (GnRH). — False. The rise in GnRH is right, but the time is wrong. Spermatogenesis starts at the age of puberty, not during embryonic development.
NCERT Extract:
Gametogenesis – “… Spermatogenesis starts at the age of puberty due to significant increase in the secretion of gonadotropin releasing hormone (GnRH). This, if you recall, is a hypothalamic hormone. The increased levels of GnRH then acts at the anterior pituitary gland and stimulates secretion of two gonadotropins – luteinising hormone (LH) and follicle stimulating hormone (FSH). LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. Androgens, in turn, stimulate the process of spermatogenesis.”