Question

Name the hormone secreted by the adrenal cortex which controls water and salt concentration in urine.
A. Adrenaline
B. Aldosterone
C. Norepinephrine
D. Corticosterone

Answer 1

Hint: It is the main mineralocorticoid hormone which is steroidal in nature. It is produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is also called salt regulating hormone.

Complete Answer:
- During the formation of urine, water and salt concentration plays a very significant role which is regulated by various mechanisms and various hormones.
- Aldosterone, also known as salt regulating hormone plays a very significant role in the regulation of sodium ion concentration in the urine. Thereby maintaining osmoregulation of the body. It is produced by the zona glomerulosa of the adrenal cortex of the adrenal gland.
- Aldosterone is primarily acting on the mineralocorticoid receptors in the distal tubules and collecting duct of the nephron. It is a part of renin-angiotensin-aldosterone system (RAAS) for regulating sodium ions and water concentration in urine.
- Aldosterone is responsible for the reabsorption of about 2% of filtered sodium in the kidneys which is nearly equal to the entire sodium content in human blood under normal glomerular filtration rates (GFR).

The correct option is B i.e. Aldosterone.

Additional information: Aldosterone helps in sodium conservation in the kidney , salivary glands, sweat glands and colon. It plays a central role in the homeostatic regulation of blood pressure, plasma sodium and potassium levels in the body. Atrial natriuretic hormone(ANF) has exactly an antagonistic( opposite) function. ANF is secreted from the atrial walls of the heart.

Note: Aldosterone was first isolated by Simpson and Tait in 1953.Aldosterone level is regulated by the RAAS, plasma concentration of potassium, ACTH ,pressure sensitive baroreceptors, plasma concentration of sodium,release of ANF. If the level of aldosterone increases then it causes conn's syndrome while the decrease level of aldosterone causes Addison's disease.