<unk> -releasing hormone<unk>  receptors are embedded in the surface of the target cell membranes and coupled to the G-protein system. Signals triggered by binding to the receptor are relayed within the cells by the cyclic AMP second messenger system.<unk> s are released under the control of<unk> -releasing hormone <unk> RH) from the arcuate nucleus and preoptic area of the hypothalamus. The gonads — testes and ovaries — are the primary target organs for<unk>  and FSH. The<unk> s affect multiple cell types and elicit multiple responses from the target organs. As a simplified generalization,<unk>  stimulates the Leydig cells of the testes and the theca cells of the ovaries to produce testosterone (and indirectly estradiol), whereas FSH stimulates the spermatogenic tissue of the testes and the granulosa cells of ovarian follicles, as well as stimulating production of estrogen by the ovaries. Although<unk> s are secreted in a pulsatile manner (as a result of pulsatile<unk> RH release), unlike the case of<unk> RH and<unk> RH agonists, constant/non-pulsatile activation of the<unk>  receptors by the<unk> s does not produce functional inhibition. This can be seen during the first 7–10 weeks of pregnancy, where constantly high and progressively-increasing levels of hCG circulate and mediate production of estrogen and progesterone by the corpus luteum until the placenta takes over the production of these hormones.
Gonadotropin
Antigonadotropin
Menotropin
Progonadotropin
Luteinizing hormone
Prolene
Androgen
Anticorticotropin