Early effects of dietary orotic acid upon liver lipid synthesis and bile cholesterol secretion in rats.

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      Dietary orotic acid is known to cause impaired fatty acid synthesis and increased cholesterol synthesis in rats. We found that the impaired fatty acid synthesis occurs during the first day of orotic acid feeding and, in studies with albumin-bound [1-14C]palmitic acid, an associated decrease in the rate of esterification of this fatty acid into triacylglycerol, phospholipid, and cholesteryl ester was observed. These changes may result from the known decreases in liver levels of adenine nucleotides or, as reported here, from decreased liver CoASH levels in orotic acid-fed rats. The increase in hepatic cholesterol synthesis occurred during the second day of orotic acid feeding. It was detected by increased incorporation of [1,2-14C]acetate into cholesterol by liver slices and by a 7-fold increase in HMG-CoA reductase activity. At the same time the biliary output of cholesterol was increased 2-fold and studies using 3H2O revealed that the output of newly synthesized cholesterol in bile was increased 5-fold. The content of cholesteryl ester in hepatic microsomes decreased during orotic acid feeding but free cholesterol was unchanged. The findings are interpreted to suggest that the increased bile cholesterol secretion caused by orotic acid is a result of impaired hepatic cholesterol esterification and that the increase in HMG-CoA reductase activity is a result of diminished negative feedback due to the depleted content of cholesteryl ester in the hepatic microsomes.


        • Standerfer S.B.
        • Handler P.
        Fatty liver induced by orotic acid feeding.
        Proc. Soc. Exp. Biol. Med. 1955; 90: 270-271
        • VonEuler L.H.
        • Rubin R.J.
        • Handschumacher R.E.
        Fatty livers induced by orotic acid. II. Changes in nucleotide metabolism.
        J. Biol. Chem. 1963; 238: 2464-2469
        • Windmueller H.G.
        An orotic acid-induced, adeninereversed inhibition of hepatic lipoprotein secretion in the rat.
        J. Biol. Chem. 1964; 239: 530-537
        • Windmueller H.G.
        • Levy R.I.
        Total inhibition of hepatic β-lipoprotein production in the rat by orotic acid.
        J. Biol. Chem. 1967; 242: 2246-2254
        • Pottenger L.A.
        • Getz G.S.
        Serum lipoprotein accumulation in the livers of orotic acid-fed rats.
        J. Lipid Res. 1971; 12: 450-459
        • Windmueller H.G.
        • Spaeth A.E.
        Perfusion in situ with tritium oxide to measure hepatic lipogenesis and lipid secretion.
        J. Biol. Chem. 1966; 241: 2891-2899
        • Haines D.S.M.
        • Rose C.I.
        Impaired labelling of liver phosphatidylethanolamine from ethanolamine 14C in choline deficiency.
        Can. J. Biochem. 1970; 48: 885-892
        • Kita T.
        • Brown M.S.
        • Goldstein J.L.
        Feedback regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase in livers of mice treated with mevinolin, a competitive inhibitor of the reductase.
        J. Clin. Invest. 1980; 65: 1094-1100
        • Jeske D.J.
        • Dietschy J.M.
        Regulation of rates of cholesterol synthesis in vivo in the liver and carcass of the rat measured using [3H]water.
        J. Lipid Res. 1980; 21: 364-376
        • Spector A.A.
        • Hoak J.C.
        An improved method for the addition of long chain free fatty acid to protein solution.
        Anal. Biochem. 1969; 32: 297-302
        • Turley S.D.
        • Dietschy J.M.
        The contribution of newly synthesized cholesterol to biliary cholesterol in the rat.
        J. Biol. Chem. 1981; 256: 2438-2446
        • Raheja R.K.
        • Kaur C.
        • Singh A.
        • Bhatia I.S.
        New colorimetric method for the quantitative estimation of phospholipids without acid digestion.
        J. Lipid Res. 1973; 14: 695697
        • Johnston P.V.
        Basic Lipid Methodology. College of Agriculture, University of Illinois, Urbana-Champaign1971: 87-88
        • Noma Y.
        • Une M.
        • Kihira K.
        • Yasuda M.
        • Kuramoto T.
        • Hoshita T.
        Bile acids and bile alcohols of bullfrog.
        J. Lipid Res. 1980; 21: 339-346
        • Turnberg L.A.
        • Anthony-Mote A.
        The quantitative determination of bile salts in bile using thin-layer chromatography and 3α-hydroxysteroid dehydrogenase.
        Clin. Chim. Acta. 1969; 24: 253-259
        • Shapiro D.J.
        • Norstorm L.J.
        • Mitschelen J.J.
        • Rodwell V.W.
        • Shimke R.T.
        Microassay for 3-hydroxy-3- methyl-glutaryl-CoA reductase in rat liver and L-cell fibroblasts.
        Biochim. Biophys. Acta. 1974; 370: 369-377
        • Bradford M.M.
        A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.
        Anal. Biochem. 1976; 72: 248-254
        • Ingebretson O.C.
        • Normann P.T.
        • Flatmark T.
        Determination of CoASH by high-performance liquid chromatography and its application in the assay of longchain acyl-CoA derivatives.
        Anal. Biochem. 1979; 96: 181-188
        • Balasubramaniam S.
        • Venkatesan S.
        • Mitropoulos K.A.
        • Peters T.J.
        The submicrosomal localization of acyl-coenzyme A-cholesterol acyltransferase and its substrate, and of cholesteryl esters in rat liver.
        Biochem. J. 1978; 174: 863-872
        • Hashimoto S.
        • Fogelman A.M.
        Smooth microsomes — a trap for cholesteryl ester formed in hepatic microsomes.
        J. Biol. Chem. 1980; 255: 8678-8684
        • Kornberg A.
        • Pricer W.E.
        Enzymatic esterification of α-glycerophosphate by lone chain fatty acids.
        J. Biol. Chem. 1953; 204: 345-357
        • Erickson S.K.
        • Shrewsbury M.A.
        • Brooks C.
        • Meyer D.J.
        Rat liver acyl-coenzyme A:cholesterol acyltransferase: its regulation in vivo and some of its properties in vitro.
        J. Lipid Res. 1980; 21: 930-941
        • Turley S.D.
        • Dietschy J.M.
        Regulation of biliary cholesterol output in the rat: dissociation from the rate of hepatic cholesterol synthesis, the size of the hepatic cholesteryl ester pool, and the hepatic uptake of chylomicron cholesterol.
        J. Lipid Res. 1979; 20: 923-934
        • Ahmed A.A.
        • McCarthy R.D.
        • Porter G.A.
        Effect of milk constituents on hepatic cholesterogenesis.
        Atherosclerosis. 1978; 32: 347-357
        • Mitropoulos K.A.
        • Venkatesan S.
        The influence of cholesterol on the activity, on the isothermic kinetics and on the temperature-induced kinetics of 3-hydroxy-3- methylglutaryl coenzyme A reductase.
        Biochim. Biophys. Acta. 1977; 489: 126-142
        • Mitropoulos K.A.
        • Balasubramaniam S.
        • Ventateran S.
        • Reeves B.E.A.
        On the mechanism for the regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase, of cholesterol 7α-hydroxylase and of acylcoenzyme A:cholesterol acyltransferase by free cholesterol.
        Biochim. Biophys. Acta. 1978; 530: 99-111
        • Brown M.S.
        • Dana S.E.
        • Goldstein J.L.
        Cholesterol ester formation in cultured human fibroblasts.
        J. Biol. Chem. 1975; 250: 4025-4027
        • Edwards P.A.
        • Popjak C.
        • Fogelman A.M.
        • Edmond J.
        Control of 3-hydroxy-3-methylglutaryl coenzyme A reductase by endogenously synthesized sterols in vitro and in vivo.
        J. Biol. Chem. 1977; 252: 1057-1063
        • Marchetti M.
        • Puddu P.
        • Caldarera C.M.
        Liver acid soluble nucleotides in orotic acid-fed rats.
        Biochem. Biophys. Acta. 1962; 61: 826-827
        • Yeh L.A.
        • Song C.S.
        • Kim K.H.
        Coenzyme A activation of acetyl-CoA carboxylase.
        J. Biol. Chem. 1981; 256: 2289-2296
        • Witters L.A.
        • Friedman S.A.
        • Tipper J.P.
        • Bacon G.W.
        Regulation of acetyl-CoA carboxylase by guanine nucleotides.
        J. Biol. Chem. 1981; 256: 8573-8578
        • Porta E.A.
        • Manning C.
        • Hartroft S.W.
        The lipotropic action of orotic acid.
        Arch. Pathol. 1968; 86: 217-229
        • Clark S.B.
        Mucosal coenzyme A-dependent cholesterol esterification after intestinal perfusion of lipids in rats.
        J. Biol. Chem. 1979; 254: 1534-1536
        • Raisonnier A.
        • Bouma M.E.
        • Solvat C.
        • Infante R.
        Metabolism of orotic acid: lack of orotate phosphoribosyltransferase in rat intestinal mucosa.
        Eur. J. Biochem. 1981; 118: 565-569
        • Ide T
        • Ontko J.A.
        Increased secretion of very low density lipoprotein triglyceride following inhibition of long chain fatty acid oxidation in isolated rat liver.
        J. Biol. Chem. 1981; 256: 10247-10255
        • Davis R.A.
        • McNeal M.M.
        • Moses R.L.
        Intrahepatic assembly of very low density lipoprotein: competition by cholesterol esters for the hydrophobic core.
        J. Biol. Chem. 1982; 257: 2634-2640
        • Creasey W.A.
        • Hankin L.
        • Handschumacher R.E.
        Fatty livers induced by orotic acid. I. Accumulation and metabolism of lipids.
        J. Biol. Chem. 1961; 236: 2064-2070
        • Haines D.S.M.
        • Tokmakjian S.D.
        The effects of dietary orotic acid on the synthesis of phosphatidylcholine in rat liver.
        Federation Proc. 1983; 42 (Abstract): 1867