Which mechanism underlies cold-induced diuresis?

Which mechanism underlies cold-induced diuresis?

• A. Peripheral vasodilation increasing central blood volume and AVP/ADH release
• B. Increased sweating reduces plasma volume causing diuresis
• C. Peripheral vasoconstriction increases central blood volume, triggering diuresis via reduced AVP/ADH and increased natriuretic peptide signaling
• D. Activation of aldosterone leading to water reabsorption and reduced urine output

Answer: (C)

Cold exposure causes peripheral blood vessels to constrict to conserve heat. This pushes more blood into the core, increasing central blood volume and atrial filling. The atria sense this stretch and release natriuretic peptides (such as ANP/BNP). These peptides promote diuresis and natriuresis by mechanisms that include dampening the antidiuretic hormone system and the renin–angiotensin–aldosterone axis, and by altering glomerular filtration and tubular handling of sodium and water. The net result is increased urine output as central blood volume rises. The idea is that central volume expansion triggers hormonal signals that favor excreting water, rather than reabsorbing it.

Cold exposure causes peripheral blood vessels to constrict to conserve heat. This pushes more blood into the core, increasing central blood volume and atrial filling. The atria sense this stretch and release natriuretic peptides (such as ANP/BNP). These peptides promote diuresis and natriuresis by mechanisms that include dampening the antidiuretic hormone system and the renin–angiotensin–aldosterone axis, and by altering glomerular filtration and tubular handling of sodium and water. The net result is increased urine output as central blood volume rises. The idea is that central volume expansion triggers hormonal signals that favor excreting water, rather than reabsorbing it.