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Normal Physiology of
Vasopressin Action
Normal Physiology of Vasopressin Action Vasopressin (also called arginine vasopressin) is released from the posterior pituitary in response to a rise in plasma osmolality and stimulates the kidneys to preserve water by concentrating urine. Within the kidneys, vasopressin binds to the arginine vasopressin type 2 receptor (AVPR2), which is expressed on the cells lining the collecting ducts. Binding of vasopressin to AVPR2 stimulates the incorporation of more water pores, formed by the protein aquaporin 2 (AQP2), into the walls of the collecting ducts. Through these water pores, water can flow out of the collecting ducts, driven by the osmotic gradient established between the tubular fluid and the renal medullary interstitium by the countercurrent mechanism. |  |
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