Phorbol ester induces loss of VIP stimulation of adenylate cyclase and VIP-binding sites in HT29 cells.
Treatment of HT29 cells with the tumor promoting phorbol ester PMA resulted in an attenuation of VIP-stimulated cAMP production in intact cells and VIP-stimulated adenylate cyclase activity in cell membranes. PMA did not decrease the ability of cholera toxin and forskolin to elevate cAMP levels in intact cells. Fluoride-stimulated adenylate cyclase activity in HT29 cells homogenates was not affected by PMA. The maximal VIP binding capacity of homogenates prepared from HT29 cells treated with PMA was decreased by 50%. It is concluded that protein kinase C regulates VIP receptor function possibly through phosphorylation of the VIP receptor.
D000230:Adenocarcinoma / Q000201:enzymology* / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism*; D001665:Binding Sites / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D010703:Phorbol Esters / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000494:pharmacology*
D010703:Phorbol Esters; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D013755:Tetradecanoylphorbol Acetate