title: Involvement of protein kinase C in prostaglandin E2-induced catecholamine release from cultured bovine adrenal chromaffin cells.
abstract: We recently reported that prostaglandin (PG) E2 stimulated phosphoinositide metabolism in cultured bovine adrenal chromaffin cells and that PGE2 and ouabain induced a gradual secretion of catecholamines from the cells (Yokohama, H., Tanaka, T., Ito, S., Negishi, M., Hayashi, H., and Hayaishi, O. (1988) J. Biol. Chem. 263, 1119-1122). Here we examined the involvement of two signal pathways, Ca2+ mobilization and protein kinase C activation resulting from phosphoinositide metabolism, in the PGE2-induced catecholamine release. Either the Ca2+ ionophore ionomycin or 12-O-tetradecanoylphorbol 13-acetate (TPA) could enhance the release in the presence of ouabain, and ionomycin-induced release was additive to PGE2-induced release, but TPA-induced release was not additive. PGE2 dose-dependently stimulated the formation of diacylglycerol and caused the translocation of 4% of the total protein kinase C activity to become membrane-bound within 5 min. These effects were specific for PGE2 and PGE1 among PGs tested (PGE2 = PGE1 greater than PGF2 alpha greater than PGD2). Furthermore, the phosphoinositide-specific phospholipase C inhibitor neomycin inhibited PGE2-induced accumulation of inositol phosphates, diacylglycerol formation, translocation of protein kinase C, and also stimulation of catecholamine release. Both PGE2- and TPA-induced release were inhibited by the depletion of protein kinase C caused by prolonged exposure to TPA, but ionomycin-induced release was not inhibited. We recently found that the amiloride-sensitive Na+, H+-antiport participates in PGE2-evoked catecholamine release (Tanaka, T., Yokohama, H., Negishi, M., Hayashi, H., Ito, S., and Hayaishi, O. (1990) J. Neurochem. 54, 86-95). In agreement with our recent report, PGE2 and TPA induced a sustained increase in intracellular pH that was abolished by the protein kinase C inhibitor staurosporine but not by the calmodulin inhibitor W-7. Ionomycin also induced a marked increase in intracellular pH, but this increase was abolished by W-7 but not by staurosporine. These results demonstrate that PGE2-induced activation of the Na+, H(+)-antiport and catecholamine release in the presence of ouabain are mediated by activation of protein kinase C, rather than by Ca2+ mobilization, resulting from phosphoinositide metabolism.
authors.affiliation: Department of Cell Biology, Osaka Bioscience Institute, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Negishi
authors.forename: S
authors.initials: S
authors.lastname: Ito
authors.forename: O
authors.initials: O
authors.lastname: Hayaishi
mesh_terms: D000313:Adrenal Medulla / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D004075:Diglycerides / Q000378:metabolism; D015232:Dinoprostone / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D010042:Ouabain / Q000494:pharmacology; D011453:Prostaglandins / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D002395:Catecholamines; D004075:Diglycerides; D011453:Prostaglandins; D015759:Ionomycin; D010042:Ouabain; D011493:Protein Kinase C; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate