Stimulation of leucine transport by a phorbol ester through activation of protein kinase C and Na+/H+ exchanger.
A synthetic diacylglycerol, 1-oleoyl-2-acetyl-sn-glycerol (OAG), as well as 12-O-tetradecanoylphorbol-13-acetate (TPA) has been found to elevate the cytoplasmic pH and increase leucine uptake dose-dependently, when added to quiescent cultures of Chang liver cell. Addition of either a protein kinase C inhibitor, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), or an Na+/H+ antiporter inhibitor, ethylisopropylamiloride (EIPA), abolished completely or incompletely the TPA-stimulated leucine uptake and TPA-induced cytoplasmic alkalinization. Therefore the stimulation of leucine uptake by OAG and TPA is proposed to be elicited at least partly through activation of Na+/H+ antiporter. We suggest that activation of protein kinase C by the phorbol ester is responsible for the stimulation of Na+/H+ exchange system and also leucine uptake in the cell.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007930:Leucine / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D002352:Carrier Proteins; D017923:Sodium-Hydrogen Exchangers; D000584:Amiloride; D011493:Protein Kinase C; D007930:Leucine; D013755:Tetradecanoylphorbol Acetate