Illustration of male hormone control, a constant regulation. The hypothalamo-hypophyseal axis : the LHRH (or GnRH) gonadotropin-releasing hormone (GnRH) released in the hypothalamus causes the hypophyseal secretion of two gonadotropin hormones (LH and FSH). The gonadotropic axis : FSH and LH, in acting on the testicles, maintains a constant concentration of testerone, and therefore male sexual characteristics. Testerone in turn limits secretions of GnRH, FSH and LH. The adrenocortical, under the control of a hypophyseal hormone (ACTH), produces a group of hormones called corticosteroids which include sexual hormones (androgens) that discretely intervene in sexual development and reproduction, but can also play an important role during pathological secretions.