Appearance of specific proteins in the apical plasma membrane of cultured renal collecting duct principal cell epithelium after chronic administration of aldosterone and arginine vasopressin.

Principal cell epithelium of renal collecting duct from neonatal rabbit kidney was cultured in the presence of aldosterone (1 x 10(-6) M) and arginine vasopressin (AVP; 1 x 10(-6) M) for 10 days to investigate, by immunohistochemical methods using specific monoclonal antibodies, whether the hormones influence the expression and insertion of plasma membrane proteins. The experiments demonstrated that aldosterone alone or aldosterone plus AVP significantly increased the number of epithelial cells reacting at the luminal and lateral plasma membrane with the antibodies CD 2 and 3, specific for renal collecting duct, as we have shown in the kidney. In cultures treated with aldosterone and aldosterone plus AVP, nearly all epithelial cells were labelled by the antibodies, while controls or AVP treatment showed 41% and 24% unreactive cells, respectively. These findings were complemented with electrophysiological experiments, in which epithelia pretreated by aldosterone or aldosterone plus AVP showed significantly hyperpolarized transepithelial voltage (Vte) and higher resistance (Rte) than controls or AVP-treated specimens. The experiments demonstrated that chronic administration of aldosterone or of aldosterone plus AVP to increase Na+-transport was paralleled by the appearance of collecting-duct-specific proteins in the epithelium. Consequently, this result indicates that aldosterone influences the functional maturity of the cultured epithelium.