Molecular characterization of nephrogenic diabetes insipidus.

Nephrogenic diabetes insipidus (NDI) is characterized by insensitivity of the distal renal nephron to the antidiuretic effect of the neurohypophyseal hormone arginine vasopressin. In the last 2 years, two different genetic defects causing the NDI phenotype have been identified. The genes involved encode proteins that reside at both ends of the cellular vasopressin signaling cascade, namely the vasopressin V(2) receptor and the aquaporin-2 water channel. Analysis of naturally occurring mutations in the V(2) receptor and the aquaporin-2 water channel will facilitate the study of structure-function correlates of both proteins, which will lead to substantial progress in elucidating the cellular mechanisms involved in the antidiuretic effect of vasopressin.