Regulation of Mg2+ uptake in isolated rat myocytes and hepatocytes by protein kinase C

[摘要]

A large Mg²⁺ cell uptake against concentration gradients is stimulated in collagenase-dispersed rut myocytes by carbachol and in hepatocytes by carbachol or vasopressin. The signalling pathway(s) responsible for this stimulation of Mg²⁺ uptake was investigated by using various activators or inhibitors of protein kinase C (PKC) and by correlating Mg²⁺ uptake with cell PKC activity and cAMP content. In both cell preparations, the direct stimulation or PKC by diacylglycerol analogs or phorbol esters reproduce the same pattern of Mg²⁺ uptake as that induced by carbachol or vasopressin, These data indicate that the activation of PKC is responsible for a stimulation of Mg²⁺ uptake by myocytes or hepatocytes, whereas increase in cAMP in these cells stimulates Mg²⁺ release.

[学科分类] 生物化学/生物物理

[关键词] Mg2+ transport;Protein kinase C;Hepatocyte;Myocyte;HEPES;4-(2-hydroxymethyl)-1 piperazine ethane sulphonic acid;PIPES;piperazine-N-N′-bis[2-ethane-sulfonic acid];EGTA;ethylene glycol-bis(b-aminoethyl ether) N;N;N′;N′;-tetraacetic acid;EDTA;ethylenediamine-tetraacetic acid;FCCP;carbonyl-cyanide p-(trifluoromethoxy-)phenylhydrazone;AA;atomic absorbance spectroscopy;OAG;1-oleoyl-2-acetyl-sn-glycerol (C18:1;[cis]-9/ C2:0);PKC;protein kinase C;SAG;1-stearoyl-2-arachidonoyl-sn-glycerol (C18:0/C20:4;[cis;cis;cis;cis]-5;8;11;14);PDBU;phorbol 12;13-dibutyrate;TPA;phorbol 12-myristate 13-acetate;H7;1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride