Oxide In Hepatocytes Research Articles

Interactions between gluconeogenesis and non-esterified fatty acid oxidation in hepatocytes from 1-day-old rats.

Conference Article| October 01 1980 Interactions between gluconeogenesis and non-esterified fatty acid oxidation in hepatocytes from 1-day-old rats SOOMANT CALLIKAN; SOOMANT CALLIKAN 1Laboratoire de Physiologie du Développement, Collège de France, 11 place Marcelin-Berthelot, 75231 Paris cedex 05, France Search for other works by this author on: This Site PubMed Google Scholar PASCAL FERRÉ; PASCAL FERRÉ 1Laboratoire de Physiologie du Développement, Collège de France, 11 place Marcelin-Berthelot, 75231 Paris cedex 05, France Search for other works by this author on: This Site PubMed Google Scholar LEILA EL MANOUBI; LEILA EL MANOUBI 1Laboratoire de Physiologie du Développement, Collège de France, 11 place Marcelin-Berthelot, 75231 Paris cedex 05, France Search for other works by this author on: This Site PubMed Google Scholar JEAN GIRARD JEAN GIRARD 1Laboratoire de Physiologie du Développement, Collège de France, 11 place Marcelin-Berthelot, 75231 Paris cedex 05, France Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1980) 8 (5): 547. https://doi.org/10.1042/bst0080547 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation SOOMANT CALLIKAN, PASCAL FERRÉ, LEILA EL MANOUBI, JEAN GIRARD; Interactions between gluconeogenesis and non-esterified fatty acid oxidation in hepatocytes from 1-day-old rats. Biochem Soc Trans 1 October 1980; 8 (5): 547. doi: https://doi.org/10.1042/bst0080547 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1980 Biochemical Society1980 Article PDF first page preview Close Modal You do not currently have access to this content.

The role of hydrogen translocating shuttles during ethanol oxidation in hepatocytes from euthyroid and hyperthyroid rats.

A quantitative study of the contribution of the malate-aspartate and glycerol-3-phosphate cycles to the translocation of reducing equivalents from cytosol to mitochondria during ethanol oxidation has been made in hepatocytes from euthyroid and hyperthyroid rats. 1. In hepatocytes from euthyroid rats both cycles have an almost equal capacity and their relative contribution to total hydrogen transport to the mitochondria depends on the conditions chosen. 2. In hepatocytes from hyperthyroid rats maximal rates of ethanol oxidation were significantly lower than in hepatocytes from euthyroid rats, even though the capacity of the glycerol-3-phosphate cycle was increased. This was due to a decreased activity of alcohol dehydrogenase.

Effect of natural amino acids on ethanol oxidation in isolated rat hepatocytes

The effects of the various naturally occurring amino acids on ethanol oxidation in hepatocytes from starved rats was systematically studied. In order to minimize the non ADH pathways, the ethanol concentration used was 4 mmol/litre, the amino acids being added at the same concentration. In hepatocytes from fasted rats, alanine, arginine, asparagine, aspartate, citrulline, cysteine, glutamate, glutamine, glycine, histidine, hydroxyproline, ornithine and serine increase significantly ethanol consumption. The stimulatory effect of glutamine being much less pronounced than the asparagine one and proline being devoid of action, the influence of ammonium chloride addition on ethanol consumption in the presence of these amino acids was studied. Ammonium chloride determines an enhancement of ethanol oxidation in these conditions, the results showing no apparent correlation between intracellular glutamate concentration and ethanol oxidation rate, contrarily to previous data. In hepatocytes from fed rats, only alanine, asparagine, cysteine, glycine, hydroxyproline, ornithine and serine increase ethanol oxidation, although to a lesser extent than in cells from starved rats.

Ethanol oxidation by isolated hepatocytes from ethanol-treated and control rats; factors contributing to the metabolic adaptation after chronic ethanol consumption

Chronic consumption of ethanol by rats produced a fatty liver and resulted in a pronounced increase in the rate of ethanol oxidation by isolated hepatocytes. Despite the increase in ethanol oxidation, oxygen consumption with several substrates was not enhanced after chronic ethanol treatment. Ouabain, an inhibitor of the (Na + + K + )-ATPase activity, did not abolish the increase in the rate of ethanol oxidation. About 40–50 per cent of the increase in ethanol oxidation persisted after inhibition of alcohol dehydrogenase, mitochondrial oxygen consumption or the malate-aspartate shuttle. The addition of substrates for the malate-aspartate shuttle slightly increased the rate of ethanol oxidation in hepatocytes from control and ethanol-treated animals. The increased rate of ethanol oxidation was not abolished by the uncoupling agent dinitrophenol. which by itself had little effect on ethanol oxidation. In the presence of aspartate or α-glycerophosphate, dinitrophenol augmented the rate of ethanol oxidation; in the presence of glutamate, the rate of ethanol oxidation was doubled by dinitrophenol. However, the higher rate of ethanol oxidation after ethanol consumption was still found in the presence of various combinations of substrate shuttles, with or without dinitrophenol. Pathways independent of alcohol dehydrogenase may contribute, at least in part, to the increase in ethanol oxidation found after chronic ethanol consumption. It is concluded that ethanol oxidation may be enhanced after chronic ethanol consumption without the estabishment of a hypermetabolic state of the liver.

Effects of ethanol on the metabolism of free fatty acids in isolated liver cells

Ethanol inhibited the oxidation and enhanced the esterification of albumin-bound [1-(14)C]palmitate incubated with isolated rat liver cells. Ethanol decreased the conversion of [1-(14)C]palmitate to (14)CO(2) and (14)C-labeled ketone bodies and enhanced the incorporation of [1-(14)C]palmitate into glycerolipids, especially triglyceride; cholesteryl ester synthesis was unaffected. The half-maximal effective ethanol concentration for each of these processes was 6-10 micro g/ml and a maximum effect was produced by about 50 micro g/ml. Ethanol oxidation was required for each of these alterations, since the effects were completely abolished by pyrazole. The energy obtainable from ethanol oxidation was in excess of the energy deficit from decreased fatty acid oxidation. However, ethanol did not affect O(2) consumption, indicating that ethanol oxidation replaced the oxidation of both fatty acids and other substrates. Ethanol inhibited the citric acid cycle in the intact liver cells by 20-30%. The major site of inhibition was alpha-ketoglutarate oxidation. Results suggest that ethanol inhibited alpha-ketoglutarate dehydrogenase in the mitochondria of hepatocytes by elevating the mitochondrial NADH:NAD ratio. A minor site of inhibition of ethanol oxidation was detected between succinate and citrate. It is suggested that ethanol inhibits fatty acid oxidation in hepatocytes by competitive substrate oxidation, resulting in an increased availability of long-chain free fatty acids; this thereby enhances esterification, leading to accumulation of liver triglyceride.