Androgen adrenal

Significant amounts of estrogens are produced by the peripheral aromatization of androgens. In human males, the peripheral aromatization of testosterone to estradiol (Ej) accounts for 80% of the production of the latter. In females, adrenal androgens are important... 

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. 

Cushing s disease and adrenal carcinomas cause adrenal androgen hypersecretion in high enough concentrations to result in signs of androgen excess (such as acne, menstrual irregularities, and hirsutism) and cause virilization in women.4... 

Discuss functions and factors regulating release of the following hormones thyroid hormones, calcitonin, parathyroid hormone, catecholamines, aldosterone, cortisol, adrenal androgens, insulin, and glucagon... 

Removal of the adrenal gland, and thus adrenal androgens, has been associated with an inhibition of sexual behavior in both humans and primates. In addition, in primates exogenous androgens, but not estrogens, reportedly reversed the effects of adrenalectomy. Exogenous androgen treatments reportedly can facilitate sexual responses in women (Sherwin, 1996). 

Pregnenolone leaves the mitochondria to become the obligatory precursor of corticosteroids and adrenal androgens. The biosynthetic pathway next branches into two separate routes. One route passes through progesterone and corticosterone to aldosterone, and the other... 

Congenital enzymatic defects in the adrenal biosynthetic pathways lead to diminished cortisol and aldosterone production and release. In these conditions, corticotrophin secretion is increased, and adrenal hyperplasia occurs, accompanied by enhanced secretion of steroid intermediates, especially adrenal androgens. More than 90% of cases of congenital adrenal hyperplasia are due to 21-hydroxylase deficiency, which is cre-afed by mufafions in fhe CYP21 gene encoding fhe en-... 

The synthesis of adrenal steroids is illustrated in Fig. 5.3.1. Cortisol, corticosterone, and aldosterone are formed by sequential hydroxylations and oxidoreductions from pregnenolone and progesterone. 17a-Hydroxypregnenolone (17HP) is a branchpoint constituent because it can be converted to cortisol or adrenal androgens. All of the components of this pathway can be quantified by MS/MS. The steroids around the periphery are urinary metabolites and these are measured by GC-MS following hydrolysis of conjugates and derivatization. 

The THEiTHF + 5aTHF ratio is commonly greater than 15 in these disorders, the opposite to AME syndrome. While the ratio of saturated steroids demonstrates a high 11-oxo l 1/1-hydroxy ratio, this is not the case for steroids retaining a - -4-ene structure. The F E ratio is normal or elevated (i.e., > 1 Table 5.3.9). Steroid profile analysis also typically reveals an elevated excretion of DHEA and other androgen metabolites. Clearly the excessive ACTH production resultant from an apparent cortisol deficiency is responsible for the elevated adrenal androgen production, which in turn is responsible for female virilization and other manifestations of polycystic ovary syndrome. 

Androgens Both the inner and middle layers of the adrenal cortex produce androgens, primarily dehydroepiandrosterone and androstenedione. Although adrenal androgens themselves are weak, they are converted in peripheral tissues to testosterone—a strong androgen—and to estradiol. 

Reduced sperm count and motility and inhibition of the secretory function of the testicles during glucocorticoid treatment have been reported and discussed in relation to the suppression of adrenal androgen production. These reports still await confirmation. 

Pygeum africanum, an extract from the bark of the African prune tree, has been used in Europe since 1969 to treat men with mild to moderate symptoms of benign prostatic hyperplasia. The mechanism of action of P. africanum is not known. In animal models, P. africanum modulates bladder contractility, has anti-inflammatory activity, decreases production of leukotrienes and other 5-lipoxygenase metabolites, inhibits fibroblast production, affects adrenal androgens, and restores the secretory activity of prostate epithelium. 

The adrenal glands play an important role in pubertal development. Termed adrenarche, the maturation of a prominent zona reticularis, the innermost layer of the cortex, begins around age six to eight in girls, resulting in increased secretion of the adrenal androgens, dehydroepiandrosterone (DHEA) and DHEA sulfate (Beckman Feuston, 2003). The rise in these hormones leads to the development of pubic and axillary hair. Recent evidence suggests... 

In the adrenal cortex, the outermost zona glomerulosa secretes the mineralocorticoid aldosterone, and corticosterone. The middle zona fasciculata and the inner zona reticularis secrete predominately the glucocorticoids cortisol and corticosterone. In the human, the inner zona reticularis secretes large amounts of the adrenal androgens, DHEA and DHEAS, as well as cortisol [12]. Whereas steroidogenesis in the... 

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