title: Protein kinase C activators and bradykinin selectively inhibit vasopressin-stimulated cAMP synthesis in MDCK cells.
abstract: To evaluate a possible modulation by protein kinase C of hormonal, cAMP-mediated effects on renal epithelial cells, we studied the effect of protein kinase C activators and of bradykinin on intracellular cAMP accumulation in MDCK cells. A 15-min pretreatment of cells with phorbol 12-myristate 13-acetate or 1-oleoyl-2-acetylglycerol induced a dose-dependent inhibition of vasopressin-stimulated cAMP synthesis, but not of basal or glucagon-, prostaglandin E2-, and forskolin-stimulated cAMP generation. 4 alpha-Phorbol 12,13-didecanoate, inactive on protein kinase C, did not affect cAMP accumulation. Bradykinin (0.1-10 microM) also inhibited the stimulatory effect of vasopressin on cAMP synthesis in a concentration-dependent manner, but affected neither basal cAMP content, nor its stimulation by glucagon, prostaglandin E2 and forskolin. The effect of activators of protein kinase C and of bradykinin occurred while renal prostaglandin synthesis was blocked with indomethacin. The inhibitory effect of protein kinase C activators and bradykinin on cAMP generation was reversed by the protein kinase C inhibitor H7, was enhanced by monensin, one effect of which is to block the recycling of membrane receptors, and persisted when the GTP-binding protein N1 was blocked with 1 mM Mn2+. Our data suggest that: protein kinase C can modulate the tubular effects of vasopressin by inhibiting cAMP generation; this effect is not mediated by renal prostaglandins, and might result from a direct action on the vasopressin receptor, or on its coupling with Ns; the modulation by bradykinin of vasopressin effects are likely to be exerted, at least partly, through activation of protein kinase C.
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D004075:Diglycerides / Q000494:pharmacology; D015232:Dinoprostone; D004789:Enzyme Activation / Q000187:drug effects; D005934:Glucagon / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology*
chemical_list: D004075:Diglycerides; D007546:Isoquinolines; D010879:Piperazines; D011458:Prostaglandins E; D014667:Vasopressins; D005576:Colforsin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C038237:1-oleoyl-2-acetylglycerol; D005934:Glucagon; D000242:Cyclic AMP; D011493:Protein Kinase C; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin