scholarly journals Induction of peroxisomal β-oxidation by a microbial catabolite of cholic acid in rat liver and cultured rat hepatocytes

1993 ◽  
Vol 295 (1) ◽  
pp. 217-220 ◽  
Author(s):  
T Nishimaki-Mogami ◽  
A Takahashi ◽  
K Toyoda ◽  
Y Hayashi
Keyword(s):  
Cholic Acid ◽  
Rat Hepatocytes ◽  
Peroxisome Proliferator ◽  
Beta Oxidation ◽  
Oxidation Activity ◽  
Cultured Rat Hepatocytes ◽  
Coa Reductase ◽  
Increased Activity

The capability of (4R)-4-(2,3,4,6,6a beta,7,8,9,9a alpha,9b beta-decahydro-6a beta-methyl-3-oxo-1H-cyclopental[f]quinolin-7 beta-yl)valeric acid (DCQVA), a catabolite of cholic acid produced by enterobacteria, to induce peroxisome proliferation in vivo and in vitro was studied. Rats given 0.3% DCQVA in the diet for 2 weeks showed marked increases in peroxisomal beta-oxidation, mitochondrial 2,4-dienoyl-CoA reductase and microsomal laurate omega-oxidation activities in the liver compared with control rats given the diet without DCQVA. Cultured rat hepatocytes treated with DCQVA for 72 h also exhibited greatly enhanced beta-oxidation activity. The increased activity was concentration-dependent and the effective concentrations were comparable with those of clofibric acid that produced the same degree of induction in the assay. The results demonstrate that DCQVA is a potent peroxisome proliferator that occurs naturally in rat intestine.

scholarly journals Antioxidant and Preventive Effects of Extract fromNymphaea candidaFlower onIn VitroImmunological Liver Injury of Rat Primary Hepatocyte Cultures

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Jun Zhao ◽  
Tao Liu ◽  
Long Ma ◽  
Ming Yan ◽  
Zhengyi Gu ◽  
...  
Keyword(s):  
Liver Injury ◽  
Antioxidant Capacity ◽  
Antioxidant Activities ◽  
Reducing Power ◽  
Rat Hepatocytes ◽  
Butylated Hydroxytoluene ◽  
Traditional Uighur Medicine ◽  
Cultured Rat Hepatocytes

Nymphaea candidais traditional Uighur medicine that is commonly used to treat head pains, cough, hepatitis and hypertension in Xinjiang of China. In this article, the extract ofN. candidawas measured for antioxidant activity, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging assay and reducing power determination, and compared with those of the positive controls of butylated hydroxytoluene (BHT) and gallic acid (GA). The active extract was further purified by liquid-liquid partition to afford four fractions, of which the ethyl acetate-soluble (EA) fraction (NCE) exhibited the strongest antioxidant capacity with IC50value of 12.6 g/mL for DPPH. Thirteen phenolic compounds were isolated from this fraction, and they all showed significant antioxidant activities in DPPH model system. Furthermore, NCE showed potent antioxidant capacity with IC50value of 59.32 g/mL, 24.48 g/mL and 86.85 g/mL, for ,·OH and H2O2radicals, respectively. Moreover, NCE on BCG plus LPS-induced immunological liver injury was evaluated using primary cultured rat hepatocytes. NCE produced significant hepatoprotective effects as evidenced by decreased supernatant enzyme activities (AST—aspartate transaminase,P<  .01; ALT—alanine transferase,P<  .01) and nitric oxide (NO,P<  .01) production. These results revealed thein vitroantioxidant and hepatoprotective activities of NCE against immunological liver injury. Further investigations are necessary to verify these activitiesin vivo.

Acidosis-induced downregulation of hepatocyte mitochondrial aquaporin-8 and ureagenesis from ammonia

2015 ◽  
Vol 93 (4) ◽  
pp. 417-420 ◽  
Author(s):  
Sara M. Molinas ◽  
Leandro R. Soria ◽  
Julieta Marrone ◽  
Mauro Danielli ◽  
Laura Trumper ◽  
...  
Keyword(s):  
Protein Expression ◽  
Culture Medium ◽  
Rat Hepatocytes ◽  
In Vivo Studies ◽  
Urea Synthesis ◽  
Primary Cultured Rat Hepatocytes ◽  
Urea Content ◽  
Cultured Rat Hepatocytes

It has been proposed that, during metabolic acidosis, the liver downregulates mitochondrial ammonia detoxification via ureagenesis, a bicarbonate-consuming process. Since we previously demonstrated that hepatocyte mitochondrial aquaporin-8 channels (mtAQP8) facilitate the uptake of ammonia and its metabolism into urea, we studied whether mtAQP8 is involved in the liver adaptive response to acidosis. Primary cultured rat hepatocytes were adapted to acidosis by exposing them to culture medium at pH 7.0 for 40 h. Control cells were exposed to pH 7.4. Hepatocytes exposed to acid medium showed a decrease in mtAQP8 protein expression (–30%, p < 0.05). Ureagenesis from ammonia was assessed by incubating the cells with 15N-labeled ammonia and measuring 15N-labeled urea synthesis by nuclear magnetic resonance. Reduced ureagenesis was found in acidified hepatocytes (–31%, p < 0.05). In vivo studies in rats subjected to 7 days acidosis also showed decreased protein expression of hepatic mtAQP8 (–50%, p < 0.05) and reduced liver urea content (–35%; p < 0.05). In conclusion, our in vitro and in vivo data suggest that hepatic mtAQP8 expression is downregulated in acidosis, a mechanism that may contribute to decreased ureagenesis from ammonia in response to acidosis.

scholarly journals Prevention of peroxisomal proliferation by carnitine palmitoyltransferase inhibitors in cultured rat hepatocytes and in vivo

1987 ◽  
Vol 245 (2) ◽  
pp. 387-392 ◽  
Author(s):  
R Hertz ◽  
J Bar–Tana
Keyword(s):  
Rat Hepatocytes ◽  
Carnitine Palmitoyltransferase ◽  
Long Chain Fatty Acids ◽  
Beta Oxidation ◽  
Carnitine Acyltransferase ◽  
Cultured Rat Hepatocytes ◽  
Acyltransferase Inhibitors ◽  
Long Chain

1. The induction of peroxisomal beta-oxidation activities by bezafibrate in cultured rat hepatocytes and in the rat in vivo was prevented by inhibitors of carnitine acyltransferase, e.g. 2-bromopalmitate, 2-[5-(4-chlorophenyl)pentyl]oxirane-2-carboxylate or 2-tetradecylglycidic acid. 2. The prevention of peroxisomal proliferation by carnitine palmitoyltransferase inhibitors could not be accounted for by inhibition of mitochondrial beta-oxidation, since 2-bromo-octanoate, acting as an inhibitor of beta-oxidation, did not prevent the induction of peroxisomal activities in cultured rat hepatocytes. 3. The putative role of the acylcarnitine derivative of bezafibrate was analysed by studying the formation of bezafibroylcarnitine with bezafibroyl-CoA as substrate. However, no bezafibroylcarnitine formation was demonstrated in the presence of rat liver preparations capable of catalysing transfer to carnitine of medium- or long-chain fatty acids. 4. The prevention of peroxisomal proliferation by carnitine acyltransferase inhibitors may help in dissecting the causal relationship between the multiple effects mediated by peroxisomal proliferators.

scholarly journals The metabolism of tetradecylthiopropionic acid, a 4-thia stearic acid, in the rat. In vivo and in vitro studies

1992 ◽  
Vol 286 (3) ◽  
pp. 879-887 ◽  
Author(s):  
E Hvattum ◽  
S Skrede ◽  
J Bremer ◽  
M Solbakken
Keyword(s):  
Stearic Acid ◽  
Rat Hepatocytes ◽  
Liver Mitochondria ◽  
Oxidation Products ◽  
Rat Liver Mitochondria ◽  
Beta Oxidation ◽  
Isolated Rat Hepatocytes ◽  
Semialdehyde Dehydrogenase

The metabolism of [1-14C]tetradecylthiopropionic acid (TTP), a 4-thia stearic acid, and its sulphoxide, [1-14C]texadecylsulphoxypropionic acid (TTP-SO), has been studied in intact rats, in isolated rat hepatocytes, and in rat liver mitochondria. Two pathways of oxidation (beta-oxidation and omega-oxidation) have been demonstrated. TTP is incorporated, in vivo, into tissue triacylglycerol and phospholipids, it is oxidized to CO2, and it is excreted in urine, mainly as carboxypropylsulphoxypropionic acid and a little as carboxymethylsulphoxypropionic acid. TTP-SO is metabolized, in vivo, more rapidly to the same two omega-oxidation products. In hepatocytes TTP is incorporated into triacylglycerol and phospholipids even more rapidly than stearic acid. It is recovered mainly in the 1-position of phosphatidylcholine. Some is oxidized to CO2 and acid-soluble products. TTP-SO is mainly omega-oxidized to the same metabolites as are found in urine. A small fraction is incorporated into phospholipids or oxidized to CO2. In isolated mitochondria [1-14C]TTP is converted into 14CO2, radioactive malonic semialdehyde, and addition products of malonic semialdehyde. In the presence of phenylhydrazine, malonic semialdehyde phenylhydrazone is the dominating product. In soluble extracts of mitochondria [1-14C]malonic semialdehyde is oxidized directly to 14CO2 in the presence of CoA and NAD+, probably by the (methyl)malonic acid semialdehyde dehydrogenase (EC 1.2.1.27).

scholarly journals Induction of cytochrome P-450 in cultured rat hepatocytes. The heterogeneous localization of specific isoenzymes using immunocytochemistry

1989 ◽  
Vol 262 (1) ◽  
pp. 151-158 ◽  
Author(s):  
R G Bars ◽  
A M Mitchell ◽  
C R Wolf ◽  
C R Elcombe
Keyword(s):  
Primary Cultures ◽  
Liver Microsomes ◽  
Rat Hepatocytes ◽  
Clofibric Acid ◽  
Maximal Concentration ◽  
Heterogeneous Distribution ◽  
Cultured Rat Hepatocytes ◽  
Cytochrome P 450

Primary cultures of rat hepatocytes were exposed to phenobarbitone, clofibric acid, beta-naphthoflavone, isosafrole or dexamethasone for 3 days, and the induction of several cytochrome P-450 isoenzymes was demonstrated by increased catalytic activity, by Western blotting and by immunocytochemistry. The profiles of isoenzymes induced in vitro were compared with those induced in liver microsomes of rats dosed with the same agents. Clofibric acid, an agent which has not been thoroughly investigated previously, was shown to induce both in vivo and in vitro several P-450 isoenzymes normally inducible by phenobarbitone (PB1a, PB3a and PB3b) or steroids (PB2c). Immunocytochemical studies demonstrated that the inducible isoenzymes of cytochrome P-450 are not distributed evenly throughout the hepatocyte population, and increasing concentrations of phenobarbitone or beta-naphthoflavone in the medium results in an increasing proportion of ‘induced’ cells. However, whereas maximal concentrations of beta-naphthoflavone resulted in virtually all cells containing induced levels of MC1b, a maximal concentration of phenobarbitone resulted in only 30% of the cells containing induced levels of PB3a/PB3b. These results are discussed in relation to the heterogeneous distribution and induction of cytochrome P-450 in the intact liver.

Distinct effects of cell-cell communication and corticosteroids on the synthesis and distribution of cytokeratins in cultured rat hepatocytes

1991 ◽  
Vol 99 (3) ◽  
pp. 609-615 ◽  
Author(s):  
G. Baffet ◽  
P. Loyer ◽  
D. Glaise ◽  
A. Corlu ◽  
P.L. Etienne ◽  
...  
Keyword(s):  
Cell Communication ◽  
Rat Hepatocytes ◽  
Culture Conditions ◽  
Adult Liver ◽  
Active Expression ◽  
Cultured Rat Hepatocytes ◽  
Rat Liver Epithelial Cells ◽  
Cell Cell

Cytokeratins CK 8 and CK 18 are the two keratins expressed in the liver. They are known to undergo extensive changes in expression with alteration of the hepatocyte phenotype in vitro. In this study, we have investigated the variation in levels of these two cytokeratins in hepatocytes selected from different situations in vivo. The amounts of corresponding transcripts were compared; cytokeratin 8 and 18 mRNAs were present at similar levels in hepatocytes freshly isolated from adult liver and, unexpectedly, from 17-day-old foetuses and newborn rats, whereas they were markedly higher in regenerating hepatocytes isolated early after partial hepatectomy. In order to investigate whether the different factors that can promote hepatocyte differentiation also produce a similar set of cytoskeletal changes, we have analysed both the expression and the distribution of cytokeratins in hepatocytes under different culture conditions allowing modulation of differentiation. Establishment of cell-cell contacts and addition of glucocorticoids were used as two modulating factors. Coculturing hepatocytes with rat liver epithelial cells (RLEC), which favours active expression of liver-specific genes, resulted in a gradual decline of cytokeratin mRNAs, whereas pure hepatocyte cultures, which exhibit rapid phenotypic changes, expressed increasing levels of CK 8 and CK 18 transcripts. Furthermore, intracellular CK distribution was dramatically modified in parallel: the CK-positive material formed a fine network of fibrils uniformly distributed in the cytoplasm of hepatocytes in pure culture, whereas in cocultured cells CK immunofluorescence appeared principally located at the cellular periphery and it was regularly arranged in long fibrils just beneath the plasma membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

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