Skip to main content
NCBI home page
Biochemical Journal logoLink to Biochemical Journal
. 1988 May 1;251(3):865–871. doi: 10.1042/bj2510865

Ethanol-induced phospholipase C activation is inhibited by phorbol esters in isolated hepatocytes.

J B Hoek 1, R Rubin 1, A P Thomas 1
PMCID: PMC1149082  PMID: 3137925

Abstract

Ethanol causes a transient activation of the phosphoinositide-specific phospholipase C in intact hepatocytes and mimics the action of receptor-mediated agonists [Hoek, Thomas, Rubin & Rubin (1987) J. Biol. Chem. 262, 682-691]. Preincubation of the hepatocytes with phorbol esters which activate protein kinase C prevented this effect of ethanol: phorbol ester treatment inhibited the ethanol-induced phosphorylase activation, the increase in intracellular free Ca2+ concentrations measured in quin 2-loaded hepatocytes, and the changes in concentrations of inositol phosphates, phosphoinositides and phosphatidic acid. Several lines of evidence indicate that these effects were mediated by protein kinase C. Phorbol esters acted in a concentration range where they activate protein kinase C; phorbol esters that do not activate protein kinase C were not effective in inhibiting the effects of ethanol. The permeant diacylglycerol oleoyl-acetylglycerol also inhibited the effects of ethanol, but other diacylglycerols were not effective in the intact cells. The inhibition of ethanol-induced Ca2+ mobilization by phorbol esters was prevented by preincubating the cells with the protein kinase C inhibitors 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H7) and sphingosine. H7 also enhanced the Ca2+ mobilization induced by ethanol in cells that were not pretreated with phorbol esters, indicating that the transient nature of the ethanol-induced Ca2+ mobilization may be due to an activation of protein kinase C caused by the accumulation of diacylglycerol. These data support a model whereby ethanol activates the phosphoinositide-specific phospholipase C, possibly by affecting receptor-G-protein-phospholipase C interactions in the membrane.

Full text

PDF
865

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Blackmore P. F., Bocckino S. B., Waynick L. E., Exton J. H. Role of a guanine nucleotide-binding regulatory protein in the hydrolysis of hepatocyte phosphatidylinositol 4,5-bisphosphate by calcium-mobilizing hormones and the control of cell calcium. Studies utilizing aluminum fluoride. J Biol Chem. 1985 Nov 25;260(27):14477–14483. [PubMed] [Google Scholar]
  2. Blackmore P. F., Exton J. H. Studies on the hepatic calcium-mobilizing activity of aluminum fluoride and glucagon. Modulation by cAMP and phorbol myristate acetate. J Biol Chem. 1986 Aug 25;261(24):11056–11063. [PubMed] [Google Scholar]
  3. Connolly T. M., Lawing W. J., Jr, Majerus P. W. Protein kinase C phosphorylates human platelet inositol trisphosphate 5'-phosphomonoesterase, increasing the phosphatase activity. Cell. 1986 Sep 12;46(6):951–958. doi: 10.1016/0092-8674(86)90077-2. [DOI] [PubMed] [Google Scholar]
  4. Cooper R. H., Coll K. E., Williamson J. R. Differential effects of phorbol ester on phenylephrine and vasopressin-induced Ca2+ mobilization in isolated hepatocytes. J Biol Chem. 1985 Mar 25;260(6):3281–3288. [PubMed] [Google Scholar]
  5. Corvera S., Schwarz K. R., Graham R. M., García-Sáinz J. A. Phorbol esters inhibit alpha 1-adrenergic effects and decrease the affinity of liver cell alpha 1-adrenergic receptors for (-)-epinephrine. J Biol Chem. 1986 Jan 15;261(2):520–526. [PubMed] [Google Scholar]
  6. Fain J. N., Li S. Y., Litosch I., Wallace M. Synergistic activation of rat hepatocyte glycogen phosphorylase by A23187 and phorbol ester. Biochem Biophys Res Commun. 1984 Feb 29;119(1):88–94. doi: 10.1016/0006-291x(84)91622-x. [DOI] [PubMed] [Google Scholar]
  7. García-Sáinz J. A., Hernández-Sotomayor S. M. Inhibitors of protein kinase C block the alpha 1-adrenergic refractoriness induced by phorbol 12-myristate 13-acetate, vasopressin and angiotensin II. Eur J Biochem. 1987 Mar 2;163(2):417–421. doi: 10.1111/j.1432-1033.1987.tb10814.x. [DOI] [PubMed] [Google Scholar]
  8. Gilboe D. P., Larson K. L., Nuttall F. Q. Radioactive method for the assay of glycogen phosphorylases. Anal Biochem. 1972 May;47(1):20–27. doi: 10.1016/0003-2697(72)90274-6. [DOI] [PubMed] [Google Scholar]
  9. Hidaka H., Inagaki M., Kawamoto S., Sasaki Y. Isoquinolinesulfonamides, novel and potent inhibitors of cyclic nucleotide dependent protein kinase and protein kinase C. Biochemistry. 1984 Oct 9;23(21):5036–5041. doi: 10.1021/bi00316a032. [DOI] [PubMed] [Google Scholar]
  10. Hoek J. B. Effects of ethanol on calcium homeostasis in rat hepatocytes and its interaction with the phosphoinositide-dependent pathway of signal transduction. Ann N Y Acad Sci. 1987;492:212–223. doi: 10.1111/j.1749-6632.1987.tb48671.x. [DOI] [PubMed] [Google Scholar]
  11. Hoek J. B., Thomas A. P., Rubin R., Rubin E. Ethanol-induced mobilization of calcium by activation of phosphoinositide-specific phospholipase C in intact hepatocytes. J Biol Chem. 1987 Jan 15;262(2):682–691. [PubMed] [Google Scholar]
  12. Irvine R. F., Anggård E. E., Letcher A. J., Downes C. P. Metabolism of inositol 1,4,5-trisphosphate and inositol 1,3,4-trisphosphate in rat parotid glands. Biochem J. 1985 Jul 15;229(2):505–511. doi: 10.1042/bj2290505. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Kelleher D. J., Johnson G. L. Phosphorylation of rhodopsin by protein kinase C in vitro. J Biol Chem. 1986 Apr 5;261(10):4749–4757. [PubMed] [Google Scholar]
  14. Kikuchi A., Ikeda K., Kozawa O., Takai Y. Modes of inhibitory action of protein kinase C in the chemotactic peptide-induced formation of inositol phosphates in differentiated human leukemic (HL-60) cells. J Biol Chem. 1987 May 15;262(14):6766–6770. [PubMed] [Google Scholar]
  15. Lapetina E. G., Reep B., Ganong B. R., Bell R. M. Exogenous sn-1,2-diacylglycerols containing saturated fatty acids function as bioregulators of protein kinase C in human platelets. J Biol Chem. 1985 Feb 10;260(3):1358–1361. [PubMed] [Google Scholar]
  16. Leeb-Lundberg L. M., Cotecchia S., Lomasney J. W., DeBernardis J. F., Lefkowitz R. J., Caron M. G. Phorbol esters promote alpha 1-adrenergic receptor phosphorylation and receptor uncoupling from inositol phospholipid metabolism. Proc Natl Acad Sci U S A. 1985 Sep;82(17):5651–5655. doi: 10.1073/pnas.82.17.5651. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Lynch C. J., Charest R., Bocckino S. B., Exton J. H., Blackmore P. F. Inhibition of hepatic alpha 1-adrenergic effects and binding by phorbol myristate acetate. J Biol Chem. 1985 Mar 10;260(5):2844–2851. [PubMed] [Google Scholar]
  18. Mazzei G. J., Katoh N., Kuo J. F. Polymyxin B is a more selective inhibitor for phospholipid-sensitive Ca2+-dependent protein kinase than for calmodulin-sensitive Ca2+-dependent protein kinase. Biochem Biophys Res Commun. 1982 Dec 31;109(4):1129–1133. doi: 10.1016/0006-291x(82)91894-0. [DOI] [PubMed] [Google Scholar]
  19. Mori T., Takai Y., Minakuchi R., Yu B., Nishizuka Y. Inhibitory action of chlorpromazine, dibucaine, and other phospholipid-interacting drugs on calcium-activated, phospholipid-dependent protein kinase. J Biol Chem. 1980 Sep 25;255(18):8378–8380. [PubMed] [Google Scholar]
  20. Orellana S., Solski P. A., Brown J. H. Guanosine 5'-O-(thiotriphosphate)-dependent inositol trisphosphate formation in membranes is inhibited by phorbol ester and protein kinase C. J Biol Chem. 1987 Feb 5;262(4):1638–1643. [PubMed] [Google Scholar]
  21. Rubin R., Thomas A. P., Hoek J. B. Ethanol does not stimulate guanine nucleotide-induced activation of phospholipase C in permeabilized hepatocytes. Arch Biochem Biophys. 1987 Jul;256(1):29–38. doi: 10.1016/0003-9861(87)90422-x. [DOI] [PubMed] [Google Scholar]
  22. Saito T., Lee J. M., Tabakoff B. Ethanol's effects on cortical adenylate cyclase activity. J Neurochem. 1985 Apr;44(4):1037–1044. doi: 10.1111/j.1471-4159.1985.tb08722.x. [DOI] [PubMed] [Google Scholar]
  23. Singh T. J., Wang J. H. Stimulation of glycogen phosphorylase kinase from rabbit skeletal muscle by organic solvents. J Biol Chem. 1979 Sep 10;254(17):8466–8472. [PubMed] [Google Scholar]
  24. Staddon J. M., Hansford R. G. 4 beta-Phorbol 12-myristate 13-acetate attenuates the glucagon-induced increase in cytoplasmic free Ca2+ concentration in isolated rat hepatocytes. Biochem J. 1986 Sep 15;238(3):737–743. doi: 10.1042/bj2380737. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Uhlemann E. R., Robberecht P., Gardner J. D. Effects of alcohols on the actions of VIP and secretin on acinar cells from guinea pig pancreas. Gastroenterology. 1979 May;76(5 Pt 1):917–925. [PubMed] [Google Scholar]
  26. Whetton A. D., Needham L., Dodd N. J., Heyworth C. M., Houslay M. D. Forskolin and ethanol both perturb the structure of liver plasma membranes and activate adenylate cyclase activity. Biochem Pharmacol. 1983 May 15;32(10):1601–1608. doi: 10.1016/0006-2952(83)90334-9. [DOI] [PubMed] [Google Scholar]
  27. van de Werve G., Proietto J., Jeanrenaud B. Control of glycogen phosphorylase interconversion by phorbol esters, diacylglycerols, Ca2+ and hormones in isolated rat hepatocytes. Biochem J. 1985 Nov 1;231(3):511–516. doi: 10.1042/bj2310511. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES