The figure given below shows the self - regulating effect of testosterone. Which option in the following table correctly identifies the terms missing from circles A and B

Answer

D

Explanation

Spermatogenesis starts at the age of puberty due to significant increase in the secretion of gonadotropin releasing hormone from hypothalamus. The increase levels of GnRH that acts at the anterior pituitary gland and stimulate secretion of FSH and LH (ICSH).
* ICSH act at the Leydig cells and stimulate synthesis and secretion of androgen. Androgen in turn stimulates the process of spermatogenesis. FSH acts on Sertoli cells and stimulate secretion of some factors which helps in Spermiogenesis. Sertoli cells secrete another protein hormone called inhibin which suppresses FSH synthesis.