Question

Which of the following does not favour the formation of large quantities of dilute urine?

• A. Renin
• B. Atrial-natriuretic factor
• C. Alcohol
• D. Caffeine

Answer 1

The correct option is A Renin

A. Renin is involved in RAAS or Renin Angiotensin Aldosterone System. Renin is secreted by juxtaglomerular cells. It activates plasma protein angiotensin which is converted to angiotensin-I. Angiotensin-I is further converted to angiotensin-II which causes increased reabsorption of water and NaCl in the proximal convoluted tubule and this results in the formation of concentrated urine.

B. Atrial natriuretic factor works opposite to RAAS and inhibits renin secretion from juxtaglomerular cells. This inhibits NaCl and water reabsorption and results in the formation of diluted urine.

C. Alcohol suppresses the secretion of ADH or antidiuretic hormone. This results in inhibition of reabsorption of water in the distal convoluted tubule and results in the formation of diluted urine.

D. Caffeine acts as a diuretic and decreases water reabsorption from the nephrons and thus, more diluted urine is produced.

Hence, it's Renin that does not favour the formation of large quantities of dilute urine instead produces concentrated urine.

So, the correct answer is 'Renin'.