Renin release by the kidney is stimulated by which condition?

Renin release by the kidney is stimulated by which condition?

• A. Decrease in extracellular fluid volume or pressure
• B. Increased plasma sodium concentration
• C. Increased dietary sodium
• D. Renal tubular reabsorption

Answer: (A)

Renin release from the kidney rises when the effective circulating volume or arterial pressure falls. The juxtaglomerular apparatus senses reduced renal perfusion or stretching of the afferent arteriole, and it also responds to signals of low NaCl delivery to the macula densa and to sympathetic stimulation. All of these cues push the kidney to release renin, kicking off the renin–angiotensin–aldosterone system to restore blood volume and pressure. If plasma sodium is high or dietary sodium is increased, the body is typically in a state of greater volume status, which tends to suppress renin release rather than stimulate it. Renal tubular reabsorption is a downstream effect that can be promoted by this system, not a direct trigger for renin release itself.

Renin release from the kidney rises when the effective circulating volume or arterial pressure falls. The juxtaglomerular apparatus senses reduced renal perfusion or stretching of the afferent arteriole, and it also responds to signals of low NaCl delivery to the macula densa and to sympathetic stimulation. All of these cues push the kidney to release renin, kicking off the renin–angiotensin–aldosterone system to restore blood volume and pressure.

If plasma sodium is high or dietary sodium is increased, the body is typically in a state of greater volume status, which tends to suppress renin release rather than stimulate it. Renal tubular reabsorption is a downstream effect that can be promoted by this system, not a direct trigger for renin release itself.