<prompt> Answer this question truthfullyWhat substance is released by the Sertoli cells, and what is its effect on the secretion of FSH?  <response>: <reason> The Sertoli cells release a substance called inhibin B, which has a negative feedback effect on the secretion of FSH follicle-stimulating hormone. Inhibin B is a hormone that is produced by the Sertoli cells in the testes of males and the ovaries of females. In males, inhibin B helps to regulate the production of sperm by inhibiting the secretion of FSH from the pituitary gland. In females, inhibin B plays a role in regulating the menstrual cycle by inhibiting the secretion of FSH and LH luteinizing hormone from the pituitary gland. The negative feedback mechanism helps to maintain a balance of hormones in the body and prevent overproduction or underproduction of hormones. 