Protein kinase C rapidly up-regulates the number of AT1 angiotensin receptors on cultured rat intestinal epithelial (RIE-1) cells.

Addition of 12-O-tetradecanoylphorbol-13-acetate to RIE-1 rat intestinal epithelial cells stimulated a rapid (mean 3-fold) increase in the subsequent binding of 125I-labelled angiotensin II which was reversed or prevented when cellular protein kinase C was depleted. The increased binding was due, in part, to an up-regulation in the number of AT1 angiotensin receptors on RIE-1 cells, without any significant change in their binding affinity. Since this rapid up-regulation was independent of receptor synthesis, it may result from an increased availability (to extracellular ligand) of performed, but previously 'cryptic', AT1 angiotensin receptors.