Which hormone regulates water reabsorption in the collecting ducts?

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Multiple Choice

Which hormone regulates water reabsorption in the collecting ducts?

Water reabsorption in the collecting ducts is controlled by antidiuretic hormone (ADH). ADH raises the permeability of the collecting duct epithelium to water by promoting the insertion of aquaporin-2 channels into the apical membrane of principal cells. With these channels present, water can be reabsorbed from the filtrate into the surrounding hyperosmotic medullary interstitium, concentrating the urine and reducing its volume. When ADH is low, aquaporin-2 channels are not present in the membrane, making the collecting ducts relatively impermeable to water and producing large volumes of dilute urine. ADH release is driven by increased plasma osmolality or decreased blood pressure/volume, detected by hypothalamic osmoreceptors and baroreceptors, with the hormone produced in the hypothalamus and released from the posterior pituitary. In contrast, erythropoietin stimulates red blood cell production; parathyroid hormone mainly regulates calcium reabsorption in the distal tubule; and aldosterone primarily increases sodium reabsorption (with water reabsorption following sodium in the distal nephron), not the direct regulation of collecting duct water permeability.

Water reabsorption in the collecting ducts is controlled by antidiuretic hormone (ADH). ADH raises the permeability of the collecting duct epithelium to water by promoting the insertion of aquaporin-2 channels into the apical membrane of principal cells. With these channels present, water can be reabsorbed from the filtrate into the surrounding hyperosmotic medullary interstitium, concentrating the urine and reducing its volume. When ADH is low, aquaporin-2 channels are not present in the membrane, making the collecting ducts relatively impermeable to water and producing large volumes of dilute urine.

ADH release is driven by increased plasma osmolality or decreased blood pressure/volume, detected by hypothalamic osmoreceptors and baroreceptors, with the hormone produced in the hypothalamus and released from the posterior pituitary. In contrast, erythropoietin stimulates red blood cell production; parathyroid hormone mainly regulates calcium reabsorption in the distal tubule; and aldosterone primarily increases sodium reabsorption (with water reabsorption following sodium in the distal nephron), not the direct regulation of collecting duct water permeability.

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