[The role of protein kinase C in the establishment of the mechanism of vasopressin antidiuretic action in the rat kidney during mammalian postnatal development].

ABSTRACT

The kidney of immaturely born mammals in early postnatal development is insensitive to the effect of the antidiuretic hormone, vasopressin. It has been demonstrated that water permeability of the epithelial cells in the collecting ducts of a rat kidney increases during development; in this process, the response to desmopressin, an agonist of vasopressin V2 receptors, appears at the age of 20 days. The observed increase in water permeability is connected with an increased content of the water channel's proteins aquaporins AQP2 and AQP3 in the plasma membrane. The calcium-dependent protein kinase C isoforms are the likely components of the vasopressin signal's transduction and are possibly involved in the mechanisms underlying the maturation of sensitivity to this hormone. The contents of three protein kinase C isoforms (alpha, delta, and zeta) in rats at different periods of their postnatal development were estimated using Western blot hybridization. It has been shown that the contents of protein kinase C isoforms alpha and delta increase with development, whereas the content of isoform zeta remains constant. The most likely participant of the mechanism providing for maturation of the cell's hormonal competence for vasopressin is the calcium-dependent protein kinase Ca, because it's content in the plasma membrane is maximal on days 20-24, which coincides with the time when the vasopressin action appears.