Question

Name the principal mineralocorticoid secreted by the adrenal cortex. What stimulates its secretion? Give it any two functions. What is the disorder caused due to excessive secretion of this hormone?

Answer 1

The name mineralocorticoid comes from early observations that these hormones play a role in the mineral sodium retention. Aldosterone is the principal endogenous mineralocorticoid, however other endogenous hormones (such as progesterone and deoxycorticosterone) also have mineralocorticoid action.

Complete answer:
Aldosterone is the most important mineralocorticoid, acting to conserve sodium ions and water in the body. The middle portion of the adrenal cortex produces glucocorticoids. Mineralocorticoids belong to the corticosteroids family of steroid hormones released by the Adrenal Medulla. Mineralocorticoids are corticosteroids that operate on renal tubules to affect salt and water balances (electrolyte balance and fluid balance.
A decrease in glomerular blood flow, glomerular blood pressure, or GFR can activate JG cells, causing them to produce renin, which transforms angiotensinogen in the blood to angiotensin I, and then to angiotensin II. Angiotensin II stimulates the secretion of aldosterone from the adrenal cortex.

Aldosterone has the following functions:
- Acts primarily on the renal tubules, promoting $Na^+$ and water reabsorption.
$K^+$ and phosphate ions are excreted.
Hyperaldosteronism is a condition marked by excessive aldosterone secretion, which results in increased sodium reabsorption and potassium and hydrogen ion loss. Hypertension (high blood pressure), hypernatremia (high blood salt content), and hypokalemia are all symptoms of apparent mineralocorticoid excess, which is an autosomal recessive condition (decreased blood potassium concentration).

Note:
Although aldosterone and cortisol have a similar affinity for the mineralocorticoid receptor, glucocorticoids circulate at a 100-fold higher concentration than mineralocorticoids. To prevent glucocorticoid overstimulation, an enzyme exists in mineralocorticoid target tissues.