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Query: UMLS:C0015695 (fatty liver)
 13,941 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fatty liver and hypolipidemia caused by aflatoxin B1 (AFB1) were studied in male Sprague-Dawley rats fed Purina Rat Chow with or without L-carnitine supplement for 6 weeks. In Experiment 1, the rats (n = 20) were divided into four groups, i.e., nonsupplemented control (NSC), nonsupplemented AFB1 (NSA), carnitine supplemented control (CSC), and carnitine supplemented AFB1 (CSA). The NSA and CSA groups were given an oral dose of [3H]AFB1 (1 mg/kg) 6 hr before kill. In Experiment 2 (n = 10) there were only NSA and CSA groups and they were killed 24 hr post-AFB1 administration. Hepatic and plasma concentrations of total lipid, triglycerides, AFB1-macromolecules adducts and urinary excretion of AFB1 were determined. Carnitine supplementation ameliorated AFB1-induced hepatic steatosis and hypolipidemia. Supplementary carnitine reduced covalent binding of AFB1 to hepatic DNA, RNA, and protein. The carnitine effect was more pronounced after 24 hr than after 6 hr of AFB1 treatment. We conclude that supplementary carnitine suppressed AFB1-induced fatty liver and AFB1-macromolecule adduct formation in the rat.
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PMID:Suppression of aflatoxin B1-induced lipid abnormalities and macromolecule-adduct formation by L-carnitine. 138 May 53

Previous studies in our laboratories have revealed that juvenile visceral steatosis mice show suppressed transcription of urea cycle enzyme genes during development and are systemically deficient in carnitine. It has not yet been explained, however, how this carnitine deficiency relates to the abnormal gene expression. We investigated the effect of carnitine on abnormal gene expression, growth retardation, and fatty liver. Carnitine administration relieved the suppression of the developmental induction of two urea cycle enzymes examined, carbamoyl-phosphate synthetase and argininosuccinate synthase, and kept the activities of enzymes normal. However, carnitine did not reduce accumulated lipid in the liver to the normal level. These results suggest that carnitine deficiency plays an important role in the abnormal expression of urea cycle enzyme genes and that the abnormal expression of the genes is not directly caused by lipid accumulation in the liver.
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PMID:Carnitine administration to juvenile visceral steatosis mice corrects the suppressed expression of urea cycle enzymes by normalizing their transcription. 154 87

We analyzed carnitine profiles in C3H-H-2 degrees strain of mouse associated with fatty liver, hyperammonemia and hypoglycemia (Koizumi et al., 1988). Carnitine levels in serum, liver and muscle of mouse with fatty liver were markedly decreased in comparison with those of control mouse (littermates without fatty liver). This is a useful animal model to analyze the role of carnitine in lipid, amino acid and carbohydrate metabolism.
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PMID:Animal model of systemic carnitine deficiency: analysis in C3H-H-2 degrees strain of mouse associated with juvenile visceral steatosis. 199 78

Patients on long-term home parenteral nutrition (HPN) are known to frequently develop hepatic steatosis or steatohepatitis. The etiology of this steatosis or steatohepatitis is unknown, but carnitine deficiency has been one of the postulated mechanisms. The importance of L-carnitine in hepatic fatty acid oxidation and the steatosis observed in primary and acquired carnitine deficiencies prompted us to determine plasma carnitine levels in 37 patients receiving long-term HPN. Thirteen patients (35%) had low total and free plasma carnitine levels. Fifteen of the 37 HPN patients were matched for age and sex with 15 patients with Crohn's disease who did not require HPN. Mean total and free plasma carnitine values were significantly lower (p less than 0.001) in these 15 HPN patients (32.2 +/- 11.9 and 28.4 +/- 10.8) when compared to Crohn's patients not requiring HPN (49.1 +/- 10.9 and 46.4 +/- 11.5). Associations were not detected between plasma carnitine and clinical or biochemical parameters that might have explained the low values.
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PMID:Plasma carnitine levels in patients receiving home parenteral nutrition. 307 43

Persistent abnormalities of liver function tests occur in approximately 15% of home parenteral nutrition (HPN) patients and are associated with steatosis, steatohepatitis, and, rarely, fibrosis or cirrhosis. Approximately one-third of patients with gut failure on long-term HPN have low total and free plasma carnitine concentrations, and it has been suggested that a deficiency of L-carnitine may be responsible for the steatosis and steatohepatitis in HPN patients. To determine whether administration of L-carnitine is capable of reversing steatosis in HPN patients, 4 adult women on HPN for a mean of 53 mo (range 21-80 mo) were studied before and after 1 mo of intravenous L-carnitine supplementation (1 g/day). All patients had abnormalities in standard liver function tests and low total and free plasma carnitine values. The mean total and free plasma carnitine concentrations and the mean total hepatic carnitine concentration were reduced before supplementation and rose to normal values after treatment (27.4 +/- 2.3 to 35.5 +/- 3.1 nmol/ml, 19.4 +/- 2.8 to 25.7 +/- 2.5 nmol/ml, and 3.5 +/- 0.65 to 6.5 +/- 1.2 nmol/mg of noncollagen protein, respectively). However, there were no significant changes in mean serum aspartate aminotransferase and alkaline phosphatase levels (65 +/- 21 vs. 54 +/- 12 IU and 429 +/- 220 vs. 472 +/- 224 IU, respectively), plasma free fatty acids, plasma triglycerides, hepatic free fatty acid and triglyceride concentrations, or the grade of hepatic steatosis on light microscopy. These results suggest that carnitine deficiency is not a major cause of steatosis and steatohepatitis in patients receiving HPN.
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PMID:L-carnitine therapy in home parenteral nutrition patients with abnormal liver tests and low plasma carnitine concentrations. 312 32

The lipid-lowering effect of carnitine and its precursors, namely lysine plus methionine, was examined in male Sprague-Dawley rats fed ethanol as 36% of the total calories. Ethanol caused typical hepatic steatosis characterized by significant accumulation of total lipids, triglycerides, cholesterols, phospholipids, and free fatty acids. Supplementation of the ethanol diet with 1% DL-carnitine, 0.5% L-lysine, and 0.2% L-methionine significantly lowered ethanol-induced increases of various lipid fractions, with the exception of free fatty acids. The lipid-lowering effect of carnitine was superior to that of its precursors and their effect together was no greater than that of carnitine alone. The triglyceride contents of liver and plasma were related inversely to the levels of carnitine and acyl carnitines. It is concluded that dietary carnitine more effectively than its precursors prevented alcohol-induced hyperlipemia and accumulation of fat in livers. Thus, a deficiency of functional carnitine may indeed exist in chronic alcoholic cases.
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PMID:Ameliorating effects of carnitine and its precursors on alcohol-induced fatty liver. 642 29

Three children in two families presented in early childhood with episodes of illness associated with fasting which resembled Reye's syndrome: coma, hypoglycemia, hyperammonemia, and fatty liver. One child died with cerebral edema during an episode. Clinical studies revealed an absence of ketosis on fasting (plasma beta-hydroxybutyrate less than 0.4 mmole/liter) despite elevated levels of free fatty acids (2.6-4.2 mmole/liter) which suggested that hepatic fatty acid oxidation was impaired. Urinary dicarboxylic acids were elevated during illness or fasting. Total carnitine levels were low in plasma (18-25 mumole/liter), liver (200-500 nmole/g), and muscle (500-800 nmole/g); however, treatment with L-carnitine failed to correct the defect in ketogenesis. Studies on ketone production from fatty acid substrates by liver tissue in vitro showed normal rates from short-chain fatty acids, but very low rates from all medium and long-chain fatty acid substrates. These results suggested that the defect was in the mid-portion of the intramitochondrial beta-oxidation pathway at the medium-chain acyl-CoA dehydrogenase step. A new assay for the electron transfer flavoprotein-linked acyl-CoA dehydrogenases was used to test this hypothesis. This assay follows the decrease in electron transfer flavoprotein fluorescence as it is reduced by acyl-CoA-acyl-CoA dehydrogenase complex. Results with octanoyl-CoA as substrate indicated that patients had less than 2.5% normal activity of medium-chain acyl-CoA dehydrogenase. The activities of short-chain and isovaleryl acyl-CoA dehydrogenases were normal; the activity of long-chain acyl-CoA dehydrogenase was one-third normal. These results define a previously unrecognized inherited metabolic disorder of fatty acid oxidation due to deficiency of medium-chain acyl-CoA dehydrogenase.
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PMID:Medium-chain acyl-CoA dehydrogenase deficiency in children with non-ketotic hypoglycemia and low carnitine levels. 664 97

Rats treated with six to eight doses (80 mg/kg, i.p.) of 4-pentenoic acid, an inhibitor of mitochondrial fatty acid oxidation in vitro, during a 48-hr starvation period developed microvesicular fatty infiltration of the liver similar to that observed in Reye's Syndrome. Hepatic triglycerides were elevated an average of 5-fold, although considerable variability was found between individual rats. Fed rats did not develop fatty liver upon similar treatment with pentenoic acid. Liver mitochondria isolated from rats with pentenoic acid-induced fatty liver showed a persistent inhibition of fatty acid oxidation. Rates of oxidation of palmitoylcarnitine and decanoylcarnitine were decreased about 70%, while that of octanoylcarnitine was decreased 50%. Carnitine-independent oxidation of octanoate was also inhibited. Oxidation rates for substrates other than fatty acids, including glutamate, succinate, pyruvate, and alpha-ketoglutarate, were unaffected. Measurements of flavoprotein reduction in intact mitochondria indicated that neither palmitoylcarnitine nor palmitoyl CoA plus L-carnitine could elicit reduction of acyl-CoA dehydrogenase and electron transferring flavoprotein in mitochondria from rats with pentenoic acid-induced fatty liver. These results support a site of inhibition of mitochondrial beta-oxidation at the level of acyl-CoA dehydrogenase for pentenoic acid treatment in vivo, and they suggest a role for nutritional or hormonal factors in the metabolic disposition of pentenoic acid in vivo and in the development of fatty liver.
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PMID:Inhibition of mitochondrial fatty acid oxidation in pentenoic acid-induced fatty liver. A possible model for Reye's syndrome. 671 30

Carnitine-mediated prevention of ethanol-induced hepatic steatosis is related to the attenuation of ethanol metabolism by carnitine in the intact rat. Although carnitine retards ethanol oxidation in the intact animal, the in vitro activities of ethanol-metabolizing enzymes remain unaltered. Therefore, hepatocytes were targeted to understand the mechanism of carnitine effect on ethanol metabolism. Rat hepatocytes were isolated by a collagenase-perfusion technique and incubated in albumin-containing medium with ethanol in the presence or absence of added carnitine or related compounds. Ethanol oxidation was determined by the loss of ethanol as well as by the products formed. The rate of ethanol oxidation in the presence of carnitine was one-half the rate in the absence of carnitine (14 vs. 25 nmol.min-1.million-1 cells). It took 100 times the concentration of carnitine to equal the maximal inhibition produced by acetylcarnitine and the effect of acetylcarnitine was without a lag time. It is concluded that acetylcarnitine is the mediator of carnitine inhibition of ethanol oxidation.
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PMID:Acetylcarnitine-mediated inhibition of ethanol oxidation in hepatocytes. 763 64

In experimental animals the enhancement of hepatic fatty acid oxidation and ketogenic capacity is accompanied by a rise in the concentration of liver carnitine. Massive obesity is characterized by enhanced fatty acid turnover, insulin resistance, and often a fatty liver. Carnitine concentrations were determined in liver, abdominal muscle tissue, and blood in morbidly obese women. The liver and muscle carnitine concentrations were significantly higher in the obese subjects than in the lean control subjects. These findings suggest an increase of the whole-body carnitine pool. In the obese subjects there was also a significant positive correlation between liver and muscle carnitine concentrations. In the majority of the obese subjects fatty changes could be demonstrated in the liver. The plasma insulin concentration tended to be positively correlated with the degree of fat infiltration and negatively correlated with the liver carnitine content. It is concluded that the liver carnitine content is significantly increased in obese women, which agrees with the finding in experimental animals.
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PMID:Increased liver carnitine content in obese women. 782 32


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