Ethanol-induced stimulation of phosphoinositide turnover and calcium influx in isolated hepatocytes.
Ethanol has been shown to mobilize intracellular calcium in isolated rat hepatocytes by activation of phosphoinositide-specific phospholipase C. However, addition of ethanol to 32P-labeled hepatocytes resulted in a rapid increase in the level of [32P]phosphatidylinositol 4-phosphate over a period of 2 min, concomitant with a small decrease in [32P]phosphatidylinositol 4,5-bisphosphate and an increase in [32P]phosphatidic acid levels. These results indicate that polyphosphatidylinositol metabolism was stimulated by ethanol simultaneously with the activation of phospholipase C. Ethanol also caused a transient increase in the influx of extracellular calcium into quin 2-loaded hepatocytes over a similar period of time. The results demonstrate that ethanol, in common with calcium-mobilizing hormones, directly or indirectly stimulated polyphosphoinositide regeneration and allowed for increased movement of calcium across the hepatocyte plasma membrane.
Rubin
R
R
Department of Pathology and Cell Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107.
Hoek
J B
JB
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008297:Male; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D010738:Type C Phospholipases / Q000032:analysis
D010716:Phosphatidylinositols; D000431:Ethanol; D010738:Type C Phospholipases; D002118:Calcium