This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology metabolism, Subject name: Physiology
During spermatogenesis Sertoli cells secrete 
Select and explain. 
A. FSH, B. LH, C. Inhibin, D. Testosterone
C: Inhibin
Answer: C: Inhibin 
Explanation: Ans. C InhibinRef: Ganong Physiology, 24th ed. pg, 419 and 420; Guyton's Physiology, 11th ed. pg. 1007* The walls of the seminiferous tubules are lined by primitive germ cells and Sertoli cells.* Maturation of spermatozoa takes place in deep folds of the cytoplasm of the sertoli cells.* Mature spermatozoa are released from the Sertoli cells and become free in the lumens of the tubules. The sertoli cells secrete androgen binding protein (ABP), inhibin, and MIS.* Inhibin inhibits follicle-stimulating hormone (FSH) secretion.* Inhibin has a strong direct effect on the anterior pituitary gland to inhibit the secretion of FSH and possibly a slight effect on the hypothalamus to inhibit secretion of GnRH.Extra Mile* Testosterone, secreted by the Leydig cells* Luteinizing hormone--by anterior pituitary gland, stimulates the Leydig cells to secrete testosterone.* FSH--also by the anterior pituitary gland, stimulates the Sertoli cells; essential for spermatogenesis.