Acute elevation of intracellular pH translocates protein kinase C activities in rat pinealocytes

The relationship between elevation of intracellular pH and activation of protein kinase C in rat pinealocytes was investigated in rat pinealocytes. It was found that direct elevation of intracellular pH alone by ammonium chloride or methylamine translocated protein kinase C activities in a dose-dependent manner. This translocation was blocked by EGTA, suggesting a requirement of Ca2+ for the process. However, elevation of intracellular pH by methylamine had no significant effect on intracellular Ca2+ or diacylglycerol content, suggesting the translocation was not due to increased intracellular Ca2+ or diacylglycerol contents. These data suggest that elevation of intracellular pH alone can trigger activation of protein kinase C through a mechanism distinct from increases in diacylglycerol or intracellular Ca2+.