Question

Two endocrine structures in testes are ..........(1) and ............ (2). They secrete ............(3) and .............. (4) hormones. These hormones inhibit ..............(5) and .............(6) hormones by feedback-mechanism.

• A. 1. Leydig cells, 2. Sertoli cells, 3. Testosterone, 4. Inhibin, 5. LH (ICSH), 6. FSH
• B. 1. Sertoli cells, 2. Leydig cells, 3. Testosterone, 4. Inhibin, 5. LH (ICSH), 6. FSH
• C. 1. Sertoli cells, 2. Leydig cells, 3. Inhibin, 4. Testosterone, 5. LH (ICSH), 6. FSH
• D. 1. Sertoli cells, 2. Leydig cells, 3. Inhibin, 4. Testosterone, 5. FSH, 6. LH (ICSH)

Answer 1

The correct option is A 1. Leydig cells, 2. Sertoli cells, 3. Testosterone, 4. Inhibin, 5. LH (ICSH), 6. FSH

Testes also exhibit endocrine nature and consist of two endocrine structures. The endocrine cells present in the space between seminiferous tubules of testes are termed as interstitial cells or interstitial cells of Leydig

(1). They serve to secrete testosterone (3). The large sustentacular cells that extend from the capsule to the lumen of the seminiferous tubule are called sertoli cells (2) which secrete inhibin (4). Testosterone and inhibin serve to block secretion of LH (5) and FSH (6). Hypothalamic gonadotropin releasing hormone (GnRH) stimulates anterior pituitary to secrete LH and FSH (gonadotropins). FSH promotes spermatogenesis in seminiferous tubules while LH stimulates Leydig cells to secrete testosterone. Testosterone secretion is regulated by feedback mechanism wherein higher blood level of the hormone negatively affects secretion of GnRH from hypothalamus which in turn lowers the secretion of FSH and LH from pituitary gland. Higher FSH blood level stimulates secretion of inhibin from sertoli cells which in turn inhibits FSH by the feedback mechanism.

Therefore, the correct answer is option A.