Abstract
The administration of a low-carbohydrate/high-saturated-fat (LC/HF) diet for 28 days or starvation for 48 h both increased pyruvate dehydrogenase kinase (PDHK) activity in extracts of rat hepatic mitochondria, by approx. 2.1-fold and 3.5-fold respectively. ELISAs of extracts of hepatic mitochondria, conducted over a range of pyruvate dehydrogenase (PDH) activities, revealed that mitochondrial immunoreactive PDHKII (the major PDHK isoform in rat liver) was significantly increased by approx. 1.4-fold after 28 days of LC/HF feeding and by approx. 2-fold after 48 h of starvation. The effect of LC/HF feeding to increase hepatic PDHK activity was retained through hepatocyte preparation, but was decreased on 21 h culture with insulin (100 micro-i.u./ml). A sustained (24 h) 2-4-fold elevation in plasma insulin concentration in vivo (achieved by insulin infusion via an osmotic pump) suppressed the effect of LC/HF feeding so that hepatic PDHK activities did not differ significantly from those of (insulin-infused) control rats. The increase in hepatic PDHK activity evoked by 28 days of LC/HF feeding was prevented and reversed (within 24 h) by the replacement of 7% of the dietary lipid with long-chain omega-3 fatty acids. Analysis of hepatic membrane lipid revealed a 1.9-fold increase in the ratio of total polyunsaturated omega-3 fatty acids to total mono-unsaturated fatty acids. The results indicate that the increased hepatic PDHK activities observed in livers of LC/HF-fed or 48 h-starved rats are associated with long-term actions to increase hepatic PDHKII concentrations. The long-term regulation of hepatic PDHK by LC/HF feeding might be achieved through an impaired action of insulin to suppress PDHK activity. In addition, the fatty acid composition of the diet, rather than the fat content, is a key influence.
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- Borkman M., Storlien L. H., Pan D. A., Jenkins A. B., Chisholm D. J., Campbell L. V. The relation between insulin sensitivity and the fatty-acid composition of skeletal-muscle phospholipids. N Engl J Med. 1993 Jan 28;328(4):238–244. doi: 10.1056/NEJM199301283280404. [DOI] [PubMed] [Google Scholar]
- Caterson I. D., Fuller S. J., Randle P. J. Effect of the fatty acid oxidation inhibitor 2-tetradecylglycidic acid on pyruvate dehydrogenase complex activity in starved and alloxan-diabetic rats. Biochem J. 1982 Oct 15;208(1):53–60. doi: 10.1042/bj2080053. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Denyer G. S., Kerbey A. L., Randle P. J. Kinase activator protein mediates longer-term effects of starvation on activity of pyruvate dehydrogenase kinase in rat liver mitochondria. Biochem J. 1986 Oct 15;239(2):347–354. doi: 10.1042/bj2390347. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fatania H. R., Vary T. C., Randle P. J. Modulation of pyruvate dehydrogenase kinase activity in cultured hepatocytes by glucagon and n-octanoate. Biochem J. 1986 Feb 15;234(1):233–236. doi: 10.1042/bj2340233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fryer L. G., Orfali K. A., Holness M. J., Saggerson E. D., Sugden M. C. The long-term regulation of skeletal muscle pyruvate dehydrogenase kinase by dietary lipid is dependent on fatty acid composition. Eur J Biochem. 1995 May 1;229(3):741–748. doi: 10.1111/j.1432-1033.1995.tb20522.x. [DOI] [PubMed] [Google Scholar]
- Ginsberg B. H., Jabour J., Spector A. A. Effect of alterations in membrane lipid unsaturation on the properties of the insulin receptor of Ehrlich ascites cells. Biochim Biophys Acta. 1982 Sep 9;690(2):157–164. doi: 10.1016/0005-2736(82)90318-2. [DOI] [PubMed] [Google Scholar]
- Grunfeld C., Baird K. L., Kahn C. R. Maintenance of 3T3-L1 cells in culture media containing saturated fatty acids decreases insulin binding and insulin action. Biochem Biophys Res Commun. 1981 Nov 16;103(1):219–226. doi: 10.1016/0006-291x(81)91682-x. [DOI] [PubMed] [Google Scholar]
- Gudi R., Bowker-Kinley M. M., Kedishvili N. Y., Zhao Y., Popov K. M. Diversity of the pyruvate dehydrogenase kinase gene family in humans. J Biol Chem. 1995 Dec 1;270(48):28989–28994. doi: 10.1074/jbc.270.48.28989. [DOI] [PubMed] [Google Scholar]
- Jones B. S., Yeaman S. J., Sugden M. C., Holness M. J. Hepatic pyruvate dehydrogenase kinase activities during the starved-to-fed transition. Biochim Biophys Acta. 1992 Mar 16;1134(2):164–168. doi: 10.1016/0167-4889(92)90040-i. [DOI] [PubMed] [Google Scholar]
- Kerbey A. L., Randle P. J. Pyruvate dehydrogenase kinase/activator in rat heart mitochondria, Assay, effect of starvation, and effect of protein-synthesis inhibitors of starvation. Biochem J. 1982 Jul 15;206(1):103–111. doi: 10.1042/bj2060103. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marchington D. R., Kerbey A. L., Giardina M. G., Jones A. E., Randle P. J. Longer-term regulation of pyruvate dehydrogenase kinase in cultured rat hepatocytes. Biochem J. 1989 Jan 15;257(2):487–491. doi: 10.1042/bj2570487. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marchington D. R., Kerbey A. L., Jones A. E., Randle P. J. Insulin reverses effects of starvation on the activity of pyruvate dehydrogenase kinase in cultured hepatocytes. Biochem J. 1987 Aug 15;246(1):233–236. doi: 10.1042/bj2460233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marchington D. R., Kerbey A. L., Jones A. E., Randle P. J. Insulin reverses effects of starvation on the activity of pyruvate dehydrogenase kinase in cultured hepatocytes. Biochem J. 1987 Aug 15;246(1):233–236. doi: 10.1042/bj2460233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mistry S. C., Priestman D. A., Kerbey A. L., Randle P. J. Evidence that rat liver pyruvate dehydrogenase kinase activator protein is a pyruvate dehydrogenase kinase. Biochem J. 1991 May 1;275(Pt 3):775–779. doi: 10.1042/bj2750775. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moir A. M., Zammit V. A. Monitoring of changes in hepatic fatty acid and glycerolipid metabolism during the starved-to-fed transition in vivo. Studies on awake, unrestrained rats. Biochem J. 1993 Jan 1;289(Pt 1):49–55. doi: 10.1042/bj2890049. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Munday M. R., Milic M. R., Takhar S., Holness M. J., Sugden M. C. The short-term regulation of hepatic acetyl-CoA carboxylase during starvation and re-feeding in the rat. Biochem J. 1991 Dec 15;280(Pt 3):733–737. doi: 10.1042/bj2800733. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Orfali K. A., Fryer L. G., Holness M. J., Sugden M. C. Long-term regulation of pyruvate dehydrogenase kinase by high-fat feeding. Experiments in vivo and in cultured cardiomyocytes. FEBS Lett. 1993 Dec 28;336(3):501–505. doi: 10.1016/0014-5793(93)80864-q. [DOI] [PubMed] [Google Scholar]
- Popov K. M., Kedishvili N. Y., Zhao Y., Shimomura Y., Crabb D. W., Harris R. A. Primary structure of pyruvate dehydrogenase kinase establishes a new family of eukaryotic protein kinases. J Biol Chem. 1993 Dec 15;268(35):26602–26606. [PubMed] [Google Scholar]
- Priestman D. A., Mistry S. C., Halsall A., Randle P. J. Role of protein synthesis and of fatty acid metabolism in the longer-term regulation of pyruvate dehydrogenase kinase. Biochem J. 1994 Jun 15;300(Pt 3):659–664. doi: 10.1042/bj3000659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Priestman D. A., Mistry S. C., Kerbey A. L., Randle P. J. Purification and partial characterization of rat liver pyruvate dehydrogenase kinase activator protein (free pyruvate dehydrogenase kinase). FEBS Lett. 1992 Aug 10;308(1):83–86. doi: 10.1016/0014-5793(92)81056-r. [DOI] [PubMed] [Google Scholar]
- Storlien L. H., Kraegen E. W., Chisholm D. J., Ford G. L., Bruce D. G., Pascoe W. S. Fish oil prevents insulin resistance induced by high-fat feeding in rats. Science. 1987 Aug 21;237(4817):885–888. doi: 10.1126/science.3303333. [DOI] [PubMed] [Google Scholar]
- Sugden M. C., Fryer L. G., Holness M. J. Regulation of hepatic pyruvate dehydrogenase kinase by insulin and dietary manipulation in vivo. Studies with the euglycaemic-hyperinsulinaemic clamp. Biochim Biophys Acta. 1996 Jun 7;1316(2):114–120. doi: 10.1016/0925-4439(96)00013-0. [DOI] [PubMed] [Google Scholar]
- Sugden M. C., Fryer L. G., Priestman D. A., Orfali K. A., Holness M. J. Increased hepatic pyruvate dehydrogenase kinase activity in fed hyperthyroid rats: studies in vivo and with cultured hepatocytes. Mol Cell Endocrinol. 1996 May 31;119(2):219–224. doi: 10.1016/0303-7207(96)03817-8. [DOI] [PubMed] [Google Scholar]
- Sugden M. C., Holness M. J. Interactive regulation of the pyruvate dehydrogenase complex and the carnitine palmitoyltransferase system. FASEB J. 1994 Jan;8(1):54–61. doi: 10.1096/fasebj.8.1.8299890. [DOI] [PubMed] [Google Scholar]
- Sugden M. C., Orfali K. A., Holness M. J. The pyruvate dehydrogenase complex: nutrient control and the pathogenesis of insulin resistance. J Nutr. 1995 Jun;125(6 Suppl):1746S–1752S. doi: 10.1093/jn/125.suppl_6.1746S. [DOI] [PubMed] [Google Scholar]
- Yorek M., Leeney E., Dunlap J., Ginsberg B. Effect of fatty acid composition on insulin and IGF-I binding in retinoblastoma cells. Invest Ophthalmol Vis Sci. 1989 Oct;30(10):2087–2092. [PubMed] [Google Scholar]