Final answer:
Sertoli cells in the testes respond to follicle-stimulating hormone (FSH) during gametogenesis, which is part of a hormonal regulation system involving GnRH, LH, and testosterone.
Step-by-step explanation:
During gametogenesis, Sertoli cells respond to the pituitary hormone known as follicle-stimulating hormone (FSH). The hypothalamus releases gonadotropin-releasing hormone (GnRH), which stimulates the anterior pituitary to secrete FSH and luteinizing hormone (LH). In the testes, FSH binds to Sertoli cells within the seminiferous tubules to promote spermatogenesis and the production of inhibins, which regulate FSH release from the pituitary and hence testosterone secretion. Conversely, LH stimulates Leydig cells to produce testosterone. This interaction is part of a negative feedback loop, where high levels of testosterone and inhibins can inhibit the production of GnRH, FSH, and LH to maintain hormonal balance.