Effects of pentobarbital and veratridine on phosphatidylinositol and phosphatidate metabolism in rat parotid acinar cells.
The metabolism of phosphatidylinositol and phosphatidate was studied in isolated rat parotid cells, incubated in a physiological buffer containing [32P]phosphate or [3H]glycerol. Carbamylcholine and epinephrine stimulated 32P incorporation into both of these phospholipids, causing their half-maximal effects at 2 and 0.8 microM respectively. The former concentration is much lower than that anticipated from binding studies. The Hill coefficients for carbamylcholine activation of 32P incorporation were 0.61 +/- 0.05 for phosphatidate and 0.64 +/- 0.05 for phosphatidylinositol. Pentobarbital (0.58 mM) inhibited the increased 32P incorporation caused by 5 microM carbamylcholine but not 100 microM carbamylcholine. Pentobarbital inhibited the incorporation of 3H equally in the presence and absence of epinephrine, indicating that the effect of pentobarbital on 32P incorporation is on turnover and not on de novo synthesis. Veratridine (200 microM) had no effect on phospholipid metabolism in the presence and absence of either carbamylcholine or epinephrine, which contrasts with our previous findings in synaptosomes [J.C. Miller and I. Leung, Biochem. J. 178, 9 (1979)].
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D005990:Glycerol / Q000378:metabolism; D066298:In Vitro Techniques; D010306:Parotid Gland / Q000378:metabolism*; D010424:Pentobarbital / Q000494:pharmacology*; D010712:Phosphatidic Acids / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D013574:Synaptosomes / Q000378:metabolism; D014701:Veratridine / Q000494:pharmacology*; D014702:Veratrine / Q000031:analogs & derivatives*
D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D014701:Veratridine; D002217:Carbachol; D014702:Veratrine; D010424:Pentobarbital; D005990:Glycerol; D004837:Epinephrine