Abstract
Studied on the oxidation of oleic and octanoic acids to ketone bodies were carried out in homogenates and in mitochondrial fractions of livers taken from fed and fasted rats. Malonyl-CoA inhibited ketogenesis from the former but not from the latter substrate. The site of inhibition appeared to be the carnitine acyltransferase I reaction. The effect was specific and easily reversible. Inhibitory concentrations were in the range of values obtained in livers from fed rats by others. It is proposed that malonyl-CoA functions as both precursor for fatty acid synthesis and suppressor of fatty acid oxidation. As such, it might be an important element in the carbohydrate-induced sparing of fatty acid oxidation.
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- DiMarco J. P., Hoppel C. Hepatic mitochondrial function in ketogenic states. Diabetes, starvation, and after growth hormone administration. J Clin Invest. 1975 Jun;55(6):1237–1244. doi: 10.1172/JCI108042. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guynn R. W., Veloso D., Veech R. L. The concentration of malonyl-coenzyme A and the control of fatty acid synthesis in vivo. J Biol Chem. 1972 Nov 25;247(22):7325–7331. [PubMed] [Google Scholar]
- Kopec B., Fritz I. B. Comparison of properties of carnitine palmitoyltransferase I with those of carnitine palmitoyltransferase II, and preparation of antibodies to carnitine palmitoyltransferases. J Biol Chem. 1973 Jun 10;248(11):4069–4074. [PubMed] [Google Scholar]
- LOSSOW W. J., CHAIKOFF I. L. Carbohydrate sparing of fatty acid oxidation. I. The relation of fatty acid chain length to the degree of sparing. II. The mechanism by which carbohydrate spares the oxidation of palmitic acid. Arch Biochem Biophys. 1955 Jul;57(1):23–40. doi: 10.1016/0003-9861(55)90173-9. [DOI] [PubMed] [Google Scholar]
- McGarry J. D., Foster D. W. Hormonal control of ketogenesis. Biochemical considerations. Arch Intern Med. 1977 Apr;137(4):495–501. [PubMed] [Google Scholar]
- McGarry J. D., Foster D. W. The regulation of ketogenesis from octanoic acid. The role of the tricarboxylic acid cycle and fatty acid synthesis. J Biol Chem. 1971 Feb 25;246(4):1149–1159. [PubMed] [Google Scholar]
- McGarry J. D., Foster D. W. The regulation of ketogenesis from oleic acid and the influence of antiketogenic agents. J Biol Chem. 1971 Oct 25;246(20):6247–6253. [PubMed] [Google Scholar]
- McGarry J. D., Guest M. J., Foster D. W. Ketone body metabolism in the ketosis of starvation and alloxan diabetes. J Biol Chem. 1970 Sep 10;245(17):4382–4390. [PubMed] [Google Scholar]
- McGarry J. D., Meier J. M., Foster D. W. The effects of starvation and refeeding on carbohydrate and lipid metabolism in vivo and in the perfused rat liver. The relationship between fatty acid oxidation and esterification in the regulation of ketogenesis. J Biol Chem. 1973 Jan 10;248(1):270–278. [PubMed] [Google Scholar]
- McGarry J. D., Robles-Valdes C., Foster D. W. Role of carnitine in hepatic ketogenesis. Proc Natl Acad Sci U S A. 1975 Nov;72(11):4385–4388. doi: 10.1073/pnas.72.11.4385. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McGarry J., Wright P. H., Foster D. W. Hormonal control of ketogenesis. Rapid activation of hepatic ketogenic capacity in fed rats by anti-insulin serum and glucagon. J Clin Invest. 1975 Jun;55(6):1202–1209. doi: 10.1172/JCI108038. [DOI] [PMC free article] [PubMed] [Google Scholar]
- NORUM K. R. PALMITYL-COA:CARNITINE PALMITYLTRANSFERASE. PURIFICATION FROM CALF-LIVER MITOCHONDRIA AND SOME PROPERTIES OF THE ENZYME. Biochim Biophys Acta. 1964 Jul 8;89:95–108. [PubMed] [Google Scholar]
- Pilkis S. J., Riou J. P., Claus T. H. Hormonal control of [14C]glucose synthesis from [U-14C]dihydroxyacetone and glycerol in isolated rat hepatocytes. J Biol Chem. 1976 Dec 25;251(24):7841–7852. [PubMed] [Google Scholar]
- Robles-Valdes C., McGarry J. D., Foster D. W. Maternal-fetal carnitine relationship and neonatal ketosis in the rat. J Biol Chem. 1976 Oct 10;251(19):6007–6012. [PubMed] [Google Scholar]