Question

Which of the following is a mineralocorticoid?
(A) Testosterone
(B) Progesterone
(C) Adrenaline
(D) Aldosterone

Answer 1

It is also a steroid hormone and produced by adrenal cortex. It also plays a critical role in regulating concentrations of water minerals - particularly sodium and potassium - in extracellular fluids.

Complete answer:
Mineralocorticoids are simply the class of corticosteroids, which are a class of steroid hormones. Mineralocorticoids are synthesized in the adrenal cortex and regulate salt and water balances. The primary mineralocorticoid is aldosterone.

Mineralocorticoids can play the great role in regulating concentrations of minerals - for sodium and potassium in extracellular fluids. The major target of aldosterone is the distal tubule of the kidney where it stimulates exchange of sodium and potassium.

Primary physiological effects of aldosterone are
(i) Increased resorption of sodium: sodium loss in urine is decreased under aldosterone stimulation.
(ii) Increased resorption of water, with consequent expansion of extracellular fluid volume.

The two most important regulators of aldosterone secretion are
(i) Concentration of the potassium ions in extracellular fluid: Small increase in the concentration in blood levels of potassium strongly stimulates the aldosterone secretion.
(ii) Angiotensin II: Activation of the renin-angiotensin system as a result of decreased renal blood flow (generally due to decreased vascular volume) results in release of angiotensin II, which can stimulate aldosterone secretion.

Hence, the correct answer is option (D) i.e., Aldosterone.

Note: The aldosterone has effects on sweat glands, salivary glands and on the colon. The net effect of aldosterone is to conserve body sodium by stimulating its resorption and in the case of the colon, absorption from the intestinal lumen.