Question

The main mineralocorticoid in human is
A. Aldosterone
B. Cortisol
C. Testosterone
D. Adrenaline

Answer 1

Hint: A class of steroid hormones that regulate water and salt balances are the Mineralocorticoids . They promote potassium and sodium transport, usually followed by changes in the water balance. This function is essential to our life.

Complete answer:
Aldosterone is the primary mineralocorticoid in humans. But other endogenous hormones such as deoxycorticosterone and progesterone have mineralocorticoid function. Aldosterone is produced in the adrenal gland cortex. It is induced primarily by angiotensin II and regulated by potassium levels and adrenocorticotropic hormone (ACTH) . The secretion of aldosterone is stimulated by four factors that are acting sequentially. The plasma α2-globulin or kininogen is the starting point, it serves as a substrate for the enzyme which is secreted by the kidney’s glomerulosa called renin . The renin clips off a 12 amino acid peptide called kininase II. Next the kininase II removes 2 amino acids from substrate angiotensin I, thus generating an octa-peptide called as angiotensin II. In the adrenal cortex’s zona glomerulosa the, the hormone angiotensin II binds to its receptor and initiates the biosynthesis of aldosterone.
The acute phase response to inflammation, whereby our body attempts to compensate for the circulatory perturbations, is associated with the dramatic increase in serum aldosterone levels. This is driven by renin-angiotensin–mediated conversion of the18-hydroxycorticosterone to aldosterone. Importantly, aldosterone secretion also is modulated by prostaglandins, serotonin, endothelins and atrial natriuretic factor and responsive to elevation of serum potassium ion and to the pituitary adrenocorticotropic hormone.

Hence, the correct answer is option (A).

Note: Through actions in the brain, Mineralocorticoids exert their effects on blood pressure as well. Although mineralocorticoid receptors have been observed in the hypothalamus and hippocampus, their role was difficult to determine until relatively recently. Through certain experiments it is observed that the concentrations of aldosterone, which would not produce visible systemic effect, can produce hypertension when directly placed into the brain.