Abstract
We previously showed that the oxidation of branched-chain amino acids is increased in rats treated with clofibrate [Paul and Adibi (1980) J. Clin. Invest. 65, 1285-1293]. Two subsequent studies have reported contradictory results regarding the effect of clofibrate treatment on gene expression of branched-chain keto acid dehydrogenase (BCKDH) in rat liver. Furthermore, there has been no previous study of the effect of clofibrate treatment on gene expression of BCKDH kinase, which regulates the activity of BCKDH by phosphorylation. The purpose of the present study was to investigate the above issues. Clofibrate treatment for 2 weeks resulted in (a) a 3-fold increase in the flux through BCKDH in mitochondria isolated from rat liver, and (b) a modest but significant increase in the activity of BCKDH. However, clofibrate treatment had no significant effect on the mass of E1 alpha, E1 beta, and E2 subunits of BCKDH or the abundance of mRNAs encoding these subunits. On the other hand, clofibrate treatment significantly reduced the activity, the protein mass and the mRNA levels of BCKDH kinase in the liver. In contrast to the results obtained in liver, clofibrate treatment had no significant effect on any of these parameters of BCKDH kinase in the skeletal muscle. In conclusion, our results show that clofibrate treatment increases the activity of BCKDH in the liver and the mechanism of this effect is the inhibition of gene expression of the BCKDH kinase.
Full Text
The Full Text of this article is available as a PDF (503.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bagchi S., Wise L. S., Brown M. L., Bregman D., Sul H. S., Rubin C. S. Structure and expression of murine malic enzyme mRNA. Differentiation-dependent accumulation of two forms of malic enzyme mRNA in 3T3-L1 cells. J Biol Chem. 1987 Feb 5;262(4):1558–1565. [PubMed] [Google Scholar]
- Baldwin J. R., Witiak D. T., Feller D. R. Disposition of clofibrate in the rat. Acute and chronic administration. Biochem Pharmacol. 1980 Dec 1;29(23):3143–3154. doi: 10.1016/0006-2952(80)90578-x. [DOI] [PubMed] [Google Scholar]
- Brandt H., Capulong Z. L., Lee E. Y. Purification and properties of rabbit liver phosphorylase phosphatase. J Biol Chem. 1975 Oct 25;250(20):8038–8044. [PubMed] [Google Scholar]
- Carothers D. J., Pons G., Patel M. S. Dihydrolipoamide dehydrogenase: functional similarities and divergent evolution of the pyridine nucleotide-disulfide oxidoreductases. Arch Biochem Biophys. 1989 Feb 1;268(2):409–425. doi: 10.1016/0003-9861(89)90309-3. [DOI] [PubMed] [Google Scholar]
- Chicco A. G., Adibi S. A., Liu W. Q., Morris S. M., Jr, Paul H. S. Regulation of gene expression of branched-chain keto acid dehydrogenase complex in primary cultured hepatocytes by dexamethasone and a cAMP analog. J Biol Chem. 1994 Jul 29;269(30):19427–19434. [PubMed] [Google Scholar]
- Chinsky J. M., Bohlen L. M., Costeas P. A. Noncoordinated responses of branched-chain alpha-ketoacid dehydrogenase subunit genes to dietary protein. FASEB J. 1994 Jan;8(1):114–120. doi: 10.1096/fasebj.8.1.7507870. [DOI] [PubMed] [Google Scholar]
- Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
- Feinberg A. P., Vogelstein B. A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem. 1983 Jul 1;132(1):6–13. doi: 10.1016/0003-2697(83)90418-9. [DOI] [PubMed] [Google Scholar]
- Fort P., Marty L., Piechaczyk M., el Sabrouty S., Dani C., Jeanteur P., Blanchard J. M. Various rat adult tissues express only one major mRNA species from the glyceraldehyde-3-phosphate-dehydrogenase multigenic family. Nucleic Acids Res. 1985 Mar 11;13(5):1431–1442. doi: 10.1093/nar/13.5.1431. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gillim S. E., Paxton R., Cook G. A., Harris R. A. Activity state of the branched chain alpha-ketoacid dehydrogenase complex in heart, liver, and kidney of normal, fasted, diabetic, and protein-starved rats. Biochem Biophys Res Commun. 1983 Feb 28;111(1):74–81. doi: 10.1016/s0006-291x(83)80119-3. [DOI] [PubMed] [Google Scholar]
- Goodwin G. W., Zhang B., Paxton R., Harris R. A. Determination of activity and activity state of branched-chain alpha-keto acid dehydrogenase in rat tissues. Methods Enzymol. 1988;166:189–201. doi: 10.1016/s0076-6879(88)66025-3. [DOI] [PubMed] [Google Scholar]
- Griffin T. A., Lau K. S., Chuang D. T. Characterization and conservation of the inner E2 core domain structure of branched-chain alpha-keto acid dehydrogenase complex from bovine liver. Construction of a cDNA encoding the entire transacylase (E2b) precursor. J Biol Chem. 1988 Oct 5;263(28):14008–14014. [PubMed] [Google Scholar]
- Harper A. E., Miller R. H., Block K. P. Branched-chain amino acid metabolism. Annu Rev Nutr. 1984;4:409–454. doi: 10.1146/annurev.nu.04.070184.002205. [DOI] [PubMed] [Google Scholar]
- Heffelfinger S. C., Sewell E. T., Danner D. J. Identification of specific subunits of highly purified bovine liver branched-chain ketoacid dehydrogenase. Biochemistry. 1983 Nov 22;22(24):5519–5522. doi: 10.1021/bi00293a011. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Laskey R. A., Mills A. D. Quantitative film detection of 3H and 14C in polyacrylamide gels by fluorography. Eur J Biochem. 1975 Aug 15;56(2):335–341. doi: 10.1111/j.1432-1033.1975.tb02238.x. [DOI] [PubMed] [Google Scholar]
- Lazarow P. B. Assay of peroxisomal beta-oxidation of fatty acids. Methods Enzymol. 1981;72:315–319. doi: 10.1016/s0076-6879(81)72021-4. [DOI] [PubMed] [Google Scholar]
- Lazarow P. B., De Duve C. A fatty acyl-CoA oxidizing system in rat liver peroxisomes; enhancement by clofibrate, a hypolipidemic drug. Proc Natl Acad Sci U S A. 1976 Jun;73(6):2043–2046. doi: 10.1073/pnas.73.6.2043. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lock E. A., Mitchell A. M., Elcombe C. R. Biochemical mechanisms of induction of hepatic peroxisome proliferation. Annu Rev Pharmacol Toxicol. 1989;29:145–163. doi: 10.1146/annurev.pa.29.040189.001045. [DOI] [PubMed] [Google Scholar]
- Miller R. H., Eisenstein R. S., Harper A. E. Effects of dietary protein intake on branched-chain keto acid dehydrogenase activity of the rat. Immunochemical analysis of the enzyme complex. J Biol Chem. 1988 Mar 5;263(7):3454–3461. [PubMed] [Google Scholar]
- Nebes V. L., Morris S. M., Jr Regulation of messenger ribonucleic acid levels for five urea cycle enzymes in cultured rat hepatocytes. Requirements for cyclic adenosine monophosphate, glucocorticoids, and ongoing protein synthesis. Mol Endocrinol. 1988 May;2(5):444–451. doi: 10.1210/mend-2-5-444. [DOI] [PubMed] [Google Scholar]
- Ono K., Shioya H., Hakozaki M., Honda K., Mori T., Kochi H. Regulation by induction of branched-chain 2-oxo acid dehydrogenase complex in clofibrate-fed rat liver. Biochem Biophys Res Commun. 1990 Oct 15;172(1):243–248. doi: 10.1016/s0006-291x(05)80200-1. [DOI] [PubMed] [Google Scholar]
- Paul H. S., Adibi S. A. Leucine oxidation and protein turnover in clofibrate-induced muscle protein degradation in rats. J Clin Invest. 1980 Jun;65(6):1285–1293. doi: 10.1172/JCI109791. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Paul H. S., Adibi S. A. Mechanism of increased conversion of branched chain keto acid dehydrogenase from inactive to active form by a medium chain fatty acid (octanoate) in skeletal muscle. J Biol Chem. 1992 Jun 5;267(16):11208–11214. [PubMed] [Google Scholar]
- Paul H. S., Adibi S. A. Role of ATP in the regulation of branched-chain alpha-keto acid dehydrogenase activity in liver and muscle mitochondria of fed, fasted, and diabetic rats. J Biol Chem. 1982 May 10;257(9):4875–4881. [PubMed] [Google Scholar]
- Paul H. S., Sekas G., Winters S. J. Role of testosterone in the induction of hepatic peroxisome proliferation by clofibrate. Metabolism. 1994 Feb;43(2):168–173. doi: 10.1016/0026-0495(94)90240-2. [DOI] [PubMed] [Google Scholar]
- Paxton R., Harris R. A. Isolation of rabbit liver branched chain alpha-ketoacid dehydrogenase and regulation by phosphorylation. J Biol Chem. 1982 Dec 10;257(23):14433–14439. [PubMed] [Google Scholar]
- Pettit F. H., Yeaman S. J., Reed L. J. Purification and characterization of branched chain alpha-keto acid dehydrogenase complex of bovine kidney. Proc Natl Acad Sci U S A. 1978 Oct;75(10):4881–4885. doi: 10.1073/pnas.75.10.4881. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Popov K. M., Shimomura Y., Harris R. A. Purification and comparative study of the kinases specific for branched chain alpha-ketoacid dehydrogenase and pyruvate dehydrogenase. Protein Expr Purif. 1991 Aug;2(4):278–286. doi: 10.1016/1046-5928(91)90084-v. [DOI] [PubMed] [Google Scholar]
- Reed L. J., Damuni Z., Merryfield M. L. Regulation of mammalian pyruvate and branched-chain alpha-keto acid dehydrogenase complexes by phosphorylation-dephosphorylation. Curr Top Cell Regul. 1985;27:41–49. doi: 10.1016/b978-0-12-152827-0.50011-6. [DOI] [PubMed] [Google Scholar]
- Rüdiger H. W., Langenbeck U., Goedde H. W. A simplified method for the preparation of 14 C-labelled branched-chain -oxo acids. Biochem J. 1972 Jan;126(2):445–446. doi: 10.1042/bj1260445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shimomura Y., Nanaumi N., Suzuki M., Popov K. M., Harris R. A. Purification and partial characterization of branched-chain alpha-ketoacid dehydrogenase kinase from rat liver and rat heart. Arch Biochem Biophys. 1990 Dec;283(2):293–299. doi: 10.1016/0003-9861(90)90645-f. [DOI] [PubMed] [Google Scholar]
- Stanko R. T., Sekas G., Isaacson I. A., Clarke M. R., Billiar T. R., Paul H. S. Pyruvate inhibits clofibrate-induced hepatic peroxisomal proliferation and free radical production in rats. Metabolism. 1995 Feb;44(2):166–171. doi: 10.1016/0026-0495(95)90260-0. [DOI] [PubMed] [Google Scholar]
- Voltti H., Savolainen M. J., Jauhonen V. P., Hassinen I. E. Clofibrate-induced increase in coenzyme A concentration in rat tissues. Biochem J. 1979 Jul 15;182(1):95–102. doi: 10.1042/bj1820095. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yeaman S. J. The 2-oxo acid dehydrogenase complexes: recent advances. Biochem J. 1989 Feb 1;257(3):625–632. doi: 10.1042/bj2570625. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zhao Y., Jaskiewicz J., Harris R. A. Effects of clofibric acid on the activity and activity state of the hepatic branched-chain 2-oxo acid dehydrogenase complex. Biochem J. 1992 Jul 1;285(Pt 1):167–172. doi: 10.1042/bj2850167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zhao Y., Popov K. M., Shimomura Y., Kedishvili N. Y., Jaskiewicz J., Kuntz M. J., Kain J., Zhang B., Harris R. A. Effect of dietary protein on the liver content and subunit composition of the branched-chain alpha-ketoacid dehydrogenase complex. Arch Biochem Biophys. 1994 Feb 1;308(2):446–453. doi: 10.1006/abbi.1994.1063. [DOI] [PubMed] [Google Scholar]