AQP2 and Hypercalcemia: Chronic hypercalcemia can induce arginine vasopressin resistance through autophagic degradation of aquaporin-2 channels in the kidneys, resulting in polyuria and dehydration.5,6 On the other hand, dehydration impairs the glomerular filtration of calcium and causes hypercalcemia, thus creating a cycle of worsening dehydration, worsening renal function, and worsening hypercalcemia.7,8