[Arginin-vasopressin-induced alterations in the structure of MDCK cells].

Alterations in the structural organization of MDCK cells under arginin-vasopressin (AVP) action were studied by electron and fluorescent microscopy. Electron-microscopical evidence was obtained that MDCK cells within monolayer form structurally distinct apical and basolateral surfaces separated by well-developed intercellular contact zones. It was proved that AVP specifically bound to the receptors on the basolateral surface of the cells, and was internalized from the surface in 10-15 min. AVP action resulted in fragmentation of Golgi apparatus and swelling of Golgi cisterns caused by initiation of osmotic water flow across the monolayer. Significant depolymerization of cells actin cytoskeleton was revealed under AVP or forskolin (an adenylate cyclase activator) exposure. Functional role and regulatory mechanisms of described structural alterations are discussed.