Cortisol is regulated by the CRH-ACTH-cortisol axis. Cortisol negatively feeds back at the hypothalamus on both CRH-producing neurons and pituitary corticotropes. CRH is regulated by several fetuswillbemasculinized.Becausetheyareunabletoproducethemineralocorticoids,aldosterone,DOC,andcorticosterone,patientswiththisdisorderhavedifficultyretainingsaltandmaintainingextracellularvolume.Consequentlytheyarelikelytobehypotensive.Iftheblockageisatthenextstep,11β-hydroxylase (CYP11B1),DOC willbeformedandlevelsofDOCwillaccumulate(see
Figs.43.8 43.9C ).BecauseDOChassignificantmineralocorticoid activity anditslevelsbecomehigh,theseindividualstendtoretainsaltandwaterandbecomehypertensive.
forms of stress, including proinflammatory cytokines, hypoglycemia, neurogenic stress, and hemorrhage, and by diurnal input.
8.
The adrenal androgens DHEA, DHEAS, and androstenedione are androgen precursors. They can be converted to active androgens peripherally and provide about 50% of circulating androgens in women. In men the role of adrenal androgens if any remains obscure. In women, adrenal androgens promote pubic and axillary hair growth and libido. Excessive adrenal androgens in women can lead to various degrees of virilization and ovarian dysfunction.
9.
The zona glomerulosa of the adrenal cortex is the site of aldosterone production. Aldosterone is the strongest naturally occurring mineralocorticoid in humans. It promotes Na+ and water reabsorption by the distal tubule and collecting duct while promoting renal K+ and H+ secretion. Aldosterone promotes Na+ and water absorption in the colon and salivary glands. It also has a proinflammatory, profibrotic effect on the cardiovascular system and causes left ventricular hypertrophy and remodeling.
10.
Major actions of angiotensin II on the adrenal cortex are increased growth and vascularity of the zona glomerulosa, increased StAR and CYP11B2 enzyme activity, and increased aldosterone synthesis.
11.
Major stimuli for aldosterone production are a rise in angiotensin II and a rise in serum [K+]. The major inhibitory signal is ANP.
12.
Addison’s disease is adrenocortical insufficiency. Common symptoms include hypotension, hyperpigmentation, muscle weakness, anorexia, hypoglycemia, and hyperkalemic acidosis.
13.
Cushing’s syndrome results from hypercortisolemia. If the basis of the disorder is increased pituitary adrenocorticotropin secretion, the disorder is called Cushing’s disease. Common symptoms of Cushing’s syndrome include centripetal fat distribution, muscle wasting, proximal muscle weakness, thin skin with abdominal striae, capillary fragility, insulin resistance, and polycythemia.
14. Congenital adrenal hyperplasia is caused by a congenital enzyme deficiency that blocks production of cortisol. The enzyme blockage results in elevated
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