Anterior pituitary, androgens

Adrenal hormone production is controlled by the hypothalamus and pituitary gland. Corticotropin-releasing hormone (CRH) is secreted by the hypothalamus and stimulates secretion of adrenocorticotropic hormone (ACTH), also known as corticotropin from the anterior pituitary. ACTH, in turn, stimulates the adrenal cortex to produce cortisol. When sufficient or excessive cortisol levels are reached, a negative feedback is exerted on the secretion of CRH and ACTH, thereby decreasing overall cortisol production. The control of adrenal androgen synthesis also follows a similar negative-feedback mechanism. 

Reproductive organs are the primary source of the steroid hormones that influence sexual and reproductive functions. In men, the testes produce testosterone and similar androgens that are responsible for spermatogenesis and the secondary sexual characteristics of adult males.7,26 In women, sexual maturation and reproductive function are governed by the production of estrogens and progestins from the ovaries.27 The release of male and female sex steroids is controlled by hormones from the hypothalamus and anterior pituitary.32 The control of male and female hormone activity and the pharmacologic implications of these hormones are discussed in Chapter 30. 

Deficiency of 17a-hydroxylase (CYP17), the enzyme required for formation of cortisol and androgens, also causes congenital adrenal hyperplasia. The genetic defect also affects the gonads, which consequently cannot synthesize androgens or estrogens. Thus, the anterior pituitary increases its output of ACTH, LH, and FSH. 

LH Luteinizing hormone a polypeptide hormone that is similar in structure to FSH and, like FSH, is synthesized and secreted from the anterior pituitary in response to binding of GnRH. It binds to receptors on the thecal cells of the ovarian follicle to increase synthesis of androgens. When binding to receptors on the corpus luteum, it increases the synthesis of progesterone. 

In the absence of the anterior pituitary and ACTH stimulation, the inner zones of the cortex atrophy, and the production of glucocorticoids and adrenal androgens is markedly impaired. Persistently elevated levels of ACTH, due either to repeated administration of large doses of ACTH or to excessive endogenous production, induce hyperplasia and hypertrophy of the inner cortical zones, with overproduction of cortisol and adrenal androgens. Adrenal hyperplasia is most marked... 

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