title: Protein kinase C activation stimulates calcium transport in adrenal zona glomerulosa cells.
abstract: Adrenal zona glomerulosa (ZG) cells produce aldosterone in response to angiotensin II and extracellular potassium through different mechanisms which involve changes in cytosolic free calcium (Cai). Protein kinase C (PKC) activation is part of the angiotensin II signalling cascade but its effects on Cai are unknown. PKC activation with 1 microM phorbol 12-myristate 13-acetate (PMA) and 8 mM Ko significantly increased the rate of calcium influx (P < 0.001). Both the PKC- and the Ko-induced calcium influx occurred via a nifedipine-sensitive pathway. When both were combined, PKC activation and 8 mM Ko were not additive over either agent alone. PKC activation and 8 mM Ko also stimulated calcium efflux (P < 0.01). When combined together PKC activation and 8 mM Ko had additive effects on calcium efflux (P < 0.05). PKC activation did not increase Cai nor the exchangeable calcium pool in contrast to 8 mM Ko which significantly increased both (P < 0.001). Thus, PKC activation in ZG cells induces a pattern of calcium transport characterized by accelerated calcium recycling across the cell membrane without increasing cell calcium content.
authors.affiliation: Division of Nephrology, School of Medicine, Second University of Naples, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cirillo
authors.forename: M
authors.initials: M
authors.lastname: Canessa
authors.forename: S
authors.initials: S
authors.lastname: Quinn
authors.forename: P R
authors.initials: PR
authors.lastname: Conlin
mesh_terms: D000311:Adrenal Glands / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics*; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation / Q000502:physiology; D007700:Kinetics; D009543:Nifedipine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015384:Zona Glomerulosa / Q000201:enzymology*
chemical_list: D011493:Protein Kinase C; D009543:Nifedipine; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium; D002118:Calcium