AVP and Hypercalcemia: Hypercalcemia leads to renal dysfunction by various mechanisms, such as renal hypoperfusion due to vasoconstriction of the afferent arteriole, hypovolemia as a consequence of sodium and water spoliation due to blockage of the Na-K-ATPase pump, dysfunction of urinary concentration mechanisms due to decreased sensitivity to antidiuretic hormone, and acute tubular necrosis resulting from intracellular calcium overload and obstruction of the renal tubules.