Vasopressin: effect on deformability of urinary surface of collecting duct cells.

In isolated renal collecting ducts vasopressin decreased the negative pressure required to suck a hemispherical bulge of the epitheliat cells' urinary surface into the tip of a micropipette. Increased surface deformability may be related to the increased permeability to water which also occurs in the apex of the cells in response to the hormone.