Action of retinoic acid on the diacylglycerol-induced ornithine decarboxylase activity, reduction in EGF binding and protein kinase C activation in rat tracheal epithelial 2C5 cells.
We have shown previously that in rat tracheal epithelial 2C5 cells the induction of ornithine decarboxylase (ODC) activity and the reduction in the binding of epidermal growth factor (EGF) by diacylglycerol is related to the activation of protein kinase C. In this paper we analyse the action of retinoic acid (RA) on these two parameters in order to determine whether RA acts on the level of protein kinase C. RA inhibits the induction of ODC activity by diacylglycerol (sn-1,2-dioctanoylglycerol) in a dose- and time-dependent manner. A biologically inactive analog of RA has no effect on this induction. RA does not affect the activation of protein kinase C by diacylglycerol in an in vitro assay. In contrast to the effect on ODC induction, RA does not counteract the reduction in EGF binding induced by diacylglycerol. These results are consistent with the concept that RA does not act at the level of protein kinase C and inhibits ODC induction during a stage following protein kinase C activation.
D000818:Animals; D002460:Cell Line; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors; D009955:Ornithine Decarboxylase / Q000096:biosynthesis*; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014132:Trachea; D014212:Tretinoin / Q000494:pharmacology*
D004075:Diglycerides; D010703:Phorbol Esters; D011956:Receptors, Cell Surface; C044295:1,2-dioctanoylglycerol; D015240:Phorbol 12,13-Dibutyrate; D014212:Tretinoin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011493:Protein Kinase C; D009955:Ornithine Decarboxylase; D013755:Tetradecanoylphorbol Acetate