Home About us Contact
|
Home About us Contact | ||
|
|
||
Hepatic Enzyme Activities (hepatic + enzyme_activity)
Selected AbstractsHepatic chemoprotective enzyme responses to 2-substituted selenazolidine-4(R)-carboxylic acidsJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2006Wael M. El-Sayed Abstract In epidemiology and human supplementation studies, as well as many animal models, selenium has shown antitumorigenic activity. The mechanism of action, however, has not been satisfactorily resolved. Selenium supplementation affects many enzymes in addition to those where selenocysteine is an essential component. Such enzymes include cytoprotective detoxifying enzymes, and the regulation of these enzymes by a set of 2-substituted selenazolidine-4(R)-carboxylic acids (SCAs) has been investigated. Following seven consecutive daily doses of these prodrugs of L -selenocysteine, changes in hepatic enzyme activities and/or mRNA levels of glutathione transferase (GST), microsomal epoxide hydrolase (mEH), NAD(P)H-quinone oxidoreductase (NQO), UDP-glucuronosyltransferase (UGT), glutathione peroxidase (GPx), and thioredoxin reductase (TR) have been observed. Among the enzymes examined, UGTs and GPx were found to be the least affected. Among the compounds, 2-oxoSCA produced the most changes and 2-phenylSCA produced the least, none. For no two compounds was the pattern of changes identical, and for a single compound, few changes were reproduced in common by the two routes of administration investigated. In general, more changes were elicited following intraperitoneal (i.p.) administration than with the intragastric (i.g.) route. This dominance was typified by 2-butylSCA and 2-cyclohexylSCA where enzyme activity elevations (TR and mEH with both, NQO with 2-butylSCA) were seen only with the i.p. route. With 2-oxoSCA, however, GST, TR, and NQO activities were found to be elevated independent of route. Only with GST (both routes) and TR (i.p. route), elevations in mRNAs accompanied the 2-oxoSCA elicited elevations of activities at the time of sacrifice. For some enzymes, most notably mEH with compounds administered i.p., elevations in mRNAs were not manifest as increased enzyme activity. Thus, although constituting a closely related series of compounds, each 2-substituted SCA produced its own unique pattern of changes, and for most members, changes were predominant following i.p. administration. © 2006 Wiley Periodicals, Inc. J Biochem Mol Toxicol 20:292,301, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20148 [source] Amelioration of oxidative stress by dandelion extract through CYP2E1 suppression against acute liver injury induced by carbon tetrachloride in sprague-dawley ratsPHYTOTHERAPY RESEARCH, Issue 9 2010Chung Mu Park Abstract The protective effects of common dandelion leaf water extract (DLWE) were investigated by carbon tetrachloride (CCl4) induced hepatitis in Sprague-Dawley rats. The animals were divided into five groups: normal control, DLWE control, CCl4 control, and two DLWE groups (0.5 and 2,g/kg bw). After 1 week of administering corresponding vehicle or DLWE, a single dose of CCl4 (50% CCl4/olive oil; 0.5,mL/kg bw) was administered 24,h before killing in order to produce acute liver injury. The DLWE treatment significantly decreased CCl4 -induced hepatic enzyme activities (AST, ALT and LDH) in a dose dependent manner. Also, the obstructed release of TG and cholesterol into the serum was repaired by DLWE administration. Hepatic lipid peroxidation was elevated while the GSH content and antioxidative enzyme activities were reduced in the liver as a result of CCl4 administration, which were counteracted by DLWE administration. Furthermore, the hepatocytotoxic effects of CCl4 were confirmed by significantly elevated Fas and TNF-? mRNA expression levels, but DLWE down-regulated these expressions to the levels of the normal control. Highly up-regulated cytochrome P450 2E1 was also lowered significantly in the DLWE groups. These results indicate that DLWE has a protective effect against CCl4 -induced hepatic damage with at least part of its effect being attributable to the attenuation of oxidative stress and inflammatory processes resulting from cytochrome P450 activation by CCl4. Copyright © 2010 John Wiley & Sons, Ltd. [source] Protective effects of N-acetyl- L -cysteine against acute carbon tetrachloride hepatotoxicity in ratsCELL BIOCHEMISTRY AND FUNCTION, Issue 1 2008Yu. Z. Maksimchik Abstract In recent years, N-acetyl- L -cysteine (NAC) has been widely investigated as a potentially useful protective and antioxidative agent to be applied in many pathological states. The aim of the present work was further evaluation of the mechanisms of the NAC protective effect under carbon tetrachloride-induced acute liver injuries in rats. The rat treatment with CCl4 (4,g/kg, intragastrically) caused pronounced hepatolysis observed as an increase in blood plasma bilirubin levels and hepatic enzyme activities, which agreed with numerous previous observations. The rat intoxication was accompanied by an enhancement of membrane lipid peroxidation (1.4-fold) and protein oxidative damage (protein carbonyl group and mixed protein-glutathione disulphide formations) in the rat liver. The levels of nitric oxide in blood plasma and liver tissue significantly increased (5.3- and 1.5-fold, respectively) as blood plasma triacylglycerols decreased (1.6-fold). The NAC administration to control and intoxicated animals (three times at doses of 150,mg/kg) elevated low-molecular-weight thiols in the liver. The NAC administration under CCl4 -induced intoxication prevented oxidative damage of liver cells, decreased membrane lipid peroxidation, protein carbonyls and mixed protein-glutathione disulphides formation, and partially normalized plasma triacylglycerols. At the same time the NAC treatment of intoxicated animals did not produce a marked decrease of the elevated levels of blood plasma ALT and AST activities and bilirubin. The in vitro exposure of human red blood cells to NAC increased the cellular low-molecular-weight thiol levels and retarded tert -butylhydroperoxide-induced cellular thiol depletion and membrane lipid peroxidation as well as effectively inhibited hypochlorous acid-induced erythrocyte lysis. Thus, NAC can replenish non-protein cellular thiols and protect membrane lipids and proteins due to its direct radical-scavenging properties, but it did not attenuate hepatotoxicity in the acute rat CCl4 -intoxication model. Copyright © 2007 John Wiley & Sons, Ltd. [source] Contraception for Women with EpilepsyEPILEPSIA, Issue 9 2006Michael D. O'Brien Summary:, Antiepileptic drugs that induce hepatic enzyme activity may alter the metabolism of most hormonal methods of contraception, and this affects the contraceptive regime. This effect should be considered in the choice of both the treatment of the epilepsy and the choice of contraceptive method. This review considers these interactions and offers advice about their management. [source] Effects of Rutin on Lipid Profile in Hypercholesterolaemic RatsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 3 2009Amir Ziaee Rutin is found in many plants and is also an important dietary constituent of food and plant-based beverages. Rutin has several pharmacological properties including antioxidant and cardioprotective activities. Also, it was identified that rutin is the major low-density lipoprotein (LDL) antioxidant compound of mulberry in an in vitro study. The effects of rutin were tested by using it as a supplement in a high-cholesterol diet. Male rats were fed a high-cholesterol diet (1 ml/100 g) for 4 weeks with rutin (10 or 100 mg/kg) or rutin 100 mg/kg and lovastatin supplementation to study the hypocholesterolaemic effects of rutin on plasma lipid levels, hepatic enzyme activity, and liver tissue. Feeding the animals a high-cholesterol diet resulted in marked hypercholesterolaemia and increased the serum level of LDL cholesterol (LDL-C). Rutin (at 100 mg/kg) alone or in combination with lovastatin significantly reduced the levels of total cholesterol, and LDL-C and also markedly decreased liver enzymes and weight in animals with a high-cholesterol diet. Our findings show that 100 mg/kg of rutin alone or with lovastatin supplementation lowered liver weight and enzymes as well as plasma total cholesterol and LDL. The hepatic histopathological results reflect the correlation of rutin and lovastatin combination with both liver weight and the levels of plasma total cholesterol and LDL-C. These results indicate that rutin in combination with lovastatin has increased anti-hypercholesterolaemic effects in an animal model. [source] Effect of dietary carbohydrate-to-lipid ratios on growth performance, body composition, nutrient utilization and hepatic enzymes activities of herbivorous grass carp (Ctenopharyngodon idella)AQUACULTURE NUTRITION, Issue 3 2010W. GAO Abstract Six isonitrogenous (390 g kg,1) and isoenergetic (16.2 kJ g,1) diets with varying carbohydrate : lipid (CHO : L) ratios (202.5,1.74), were fed to triplicate groups of 25 fish in indoor recirculation system. Over 8-week-growth trial, best weight gain (WG), specific growth rate, feed conversion ratio, protein efficiency ratio and protein production value (P < 0.05) were observed in fish-fed diets with CHO : L ratio of 7.5. Fish fed either the lowest (1.7) or highest (202.5) CHO : L ratio tended to produce lower (P < 0.05) growth and feed conversion efficiencies. The values of viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio increased as dietary CHO : L ratios decreased. There were no significant differences in whole body and liver crude protein among dietary treatments. Whole body and liver lipid increased as CHO : L ratios decreased. Plasma cholesterol and triacylglyceride levels increased linearly as dietary CHO : L ratios decreased. Activities of glucokinase and pyruvate kinase were stimulated by elevated levels of dietary carbohydrate; however, activities of lipase (LPS) and alkaline phosphatase were stimulated by elevated levels of dietary lipid. Based on a second-order polynomial regression analysis of WG against dietary carbohydrate and lipid levels, 275 g kg,1 of carbohydrate and 59 g kg,1 of lipid, corresponding to a CHO : L ratio of 4.7, in a diet holding 390 g kg,1 of crude protein and 16.3 kJ g,1 of gross energy, proved to be optimal for grass carp. These results indicated that utilization of dietary lipid and carbohydrate was moderate in grass carp, but the fish were a little more capable of utilizing lipid compared with carbohydrate. [source] | ||||||||||