Endocrine Abstracts

The water channel aquaporin-2 (AQP2) of the kidney connecting tubule and collecting ducts, plays an essential role in maintaining body water balance. AQP2 is regulated by the peptide hormone arginine vasopressin (AVP), which exerts parts of its effects through the type 2 vasopressin receptor (AVPR2), expressed throughout the distal nephron. Disrupted function or regulation of AQP2 or the AVPR2 results in nephrogenic diabetes insipidus (NDI). NDI is a common clinical condition of renal origin, which is most often characterized by polydipsia and polyuria. Major research efforts have advanced our understanding of NDI at the genetic, cellular, molecular, and biological levels. In this talk I provide an overview of the cell biological causes of NDI. In addition, I provide an overview of the new treatment strategies that have been recently proposed for alleviating the symptoms of some forms of NDI, such as those arising from lithium and other drug therapies, acute and chronic renal failure, and disturbed levels of calcium and potassium. I will also discuss cell biological mechanisms for bypassing G protein-coupled receptor signaling.