Testosterone is a steroid hormone produced by all vertebrate animals and, in humans and other mammals, it is secreted in large amounts by the testes of males and, to a much lesser extent, the ovaries of females.
In adult males, testosterone plays a key role in the development of reproductive organs, and it promotes the secondary sexual characteristics of body and facial hair, increased muscle and bone mass, and a deep voice. Testosterone, like all hormones, works via long distance signaling and is regulated by other hormones as illustrated below:
When testosterone levels are low, gonadotropin-releasing hormone (GnRH) is released by the hypothalamus, which in turn stimulates the pituitary gland to release FSH and LH. FSH and LH then stimulate the testes to produce testosterone.
Which of the following describes how homeostasis is achieved when testosterone levels begin to rise?