aldosterone

aldosterone , steroid secreted by the cortex of the adrenal gland. It is the most potent hormone regulating the body's electrolyte balance. Aldosterone acts directly on the kidney to decrease the rate of sodium-ion excretion (with accompanying retention of water), and to increase the rate of potassium-ion excretion. The secretion of aldosterone appears to be regulated by two mechanisms. First, the concentration of sodium ions may be a factor since increased rates of aldosterone secretion are found when dietary sodium is severely limited. Second, reduced blood flow to the kidney stimulates certain kidney cells to secrete the proteolytic enzyme renin, which converts the inactive angiotensinogen globulin in the blood into angiotensin I. Another enzyme then converts angiotensin I into angiotensin II, its active form. This peptide, in turn, stimulates the secretion of aldosterone by the adrenal cortex. Pathologically elevated aldosterone secretion with concomitant excessive retention of salt and water often results in edema.

aldosterone A steroid hormone secreted by the adrenal cortex which controls the excretion of salts and water by the kidneys.

aldosterone A steroid hormone that is synthesized by the adrenal cortex (adrenal gland). It influences electrolyte balance by promoting the retention by the body of sodium ions and the excretion of those of potassium; it also affects the rate of carbohydrate metabolism.