• BMB Reports
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• 제30권1호
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• pp.73-79
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• 1997

This study was designed to investigate the effects of dietary garlic powder on cytochrome P450 enzymes and membrane stability in murine hepatocarcinogenesis initiated by diethylnitrosamine (DEN). Male Sprague-Dawley rats received a single intraperitoneal injection of DEN (200 mg/kg body wt) dissolved in saline. After 2 weeks on a basal diet, animals were fed diets containing 0. 0.5. 2.0. or 5.0% garlic powder for 6 weeks, and were subjected to two-thirds partial hepatectomy. The areas of placental glutathione S-transferase (GST-P) positive foci were inhibited in rats fed with garlic diets. GST-P is the most effective marker for DEN-initiated lesions. Hepatic microsomal lipid peroxidation was significantly decreased in rats fed with 2.0 and 5.0% garlic powder diets compared with that observed in the control animals and hepatic microsomal glucose 6-phosphatase (G6Pase) activity was found to increase significantly in rats fed 0.5 and 2.0% garlic powder diets. Thus as little as 0.5% garlic powder has a positive effect on the stability of hepatic microsomal membranes. p-Nitrophenol hydroxylase (PNPH) activity and the level of cytochrome P450 2E1 protein in the hepatic microsomes from rats fed diets containing 2.0 and 5.0% garlic powder were much lower than those of control microsomes. Rats fed 5.0% garlic powder diets exhibited the lowest P450 2E1 activity and protein levels among groups. Pentoxyresorufin O-dealkylase activity and immunoblot (cytochrome P450 2B1) analyses were not different between groups. However, the levels of cytochrome P450 1A1/2 protein in rats fed 0.5 and 2.0% garlic powder were significantly induced compared to controls. These results suggest that 2.0% garlic powder is effective in inhibiting the areas of GST-P positive foci, modulating certain isoforms of cytochrome P450 enzymes and stabilizing the hepatic microsomal membrane. Thus, the selective modification of cytochrome P450 enzymes and membrane stability by dietary garlic powder may influence areas of GST-P positive foci and chemoprevention of post-initiation of rat hepatocarcinogenesis.

• Journal of Nutrition and Health
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• 제35권6호
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• pp.643-649
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• 2002

This study was done to investigate effects of ${\gamma}$-irradiated pork feeding on the formation of glutathione S-transferase placental form positive (GST-P$^{+}$) foci, lipid peroxidation, cytochrome P450 system and microsomal glucose 6-phosphatase activity in diethylnitrosamine (DEN)-initiated rat hepatocarcinogenesis. Weaning Sprague-Dawley male rats were fed the diet containing ${\gamma}$-irradiated ground pork at the dose of 0, 3, 10, 30 kGy as a 20％ of protein source for 8 weeks. One week after feeding, rats were intraperitoneally injected twice with a dose of DEN (50 mg/kg BW). As a promote.,0.05％phenobarbital was fed in drinking water from one week after DEN treatment until the end of experiment. At the end of 8th week, rats were sacrificed and hepatic GST-P$^{+}$ foci, microsomal malondialdehyde (MDA) and conjugated diene contents were determined. In addition, cytochrome P450 content and the activities of NADPH cytochrome P450 reductase and glucose 6-phosphatase were also measured. There was no significant effect by gamma irradiation on microsomal MDA content, conjugated diene, cytochrome P450 content and activities of NADPH cytochrome P450 reductase and glucose 6-phosphatase. However with DEN treatment, microsomal MDA content showed a increasing tendency. Cytochrome P450 content was also significantly increased while microsomal glucose 6-phophatase activity was significantly decreased with DEN treatment. However the activity of NADPH cytochrome P450 reductase was not affected. An interesting finding in this study was that the number and area of hepatic GST-P$^{+}$ foci of rats fed gamma irradiated pork were tended to be decreased by high dose of irradiation, but were not significantly different. These results might imply that the consumption of low dose of gamma irradiated pork does not affect the formation of hepatic GST-P$^{+}$ foci and lipid peroxide and membrane stability.ability.

• 한국식품영양과학회지
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• 제28권3호
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• pp.638-645
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• 1999

This study was done to investigate effects of ${\gamma}$ irradiated beef feeding on the formation of gluta thione S transferase placental form positive(GST P+) foci, lipid peroxidation, cytochrome P450 system and microsomal glucose 6 phosphate activity in diethylnitrosamine(DEN) initiated rat hepatocarci nogenesis. Weaning Sprague Dawley male rats were fed the diet containing ${\gamma}$ irradiatied ground beef at the dose of 0, 3, 5kGy as a 20% of protein source for 8 weeks. One week after feeding, rats were intraperitoneally injected twice with a dose of DEN(50mg/kg BW). As a promoter, 0.05% phenobarbital was fed in drinking water from one week after DEN treatment until the end of experiment. At the end of 8th week, rats were sacrificed and hepatic GST P+ foci, microsomal malondialdehyde(MDA) and conjugated diene contents were determined. In addition, cytochrome P450 content and the activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase were also measured. There was no significant effect by gamma irradiation on microsomal MDA content, conjugated diene, cytochrome P450 content and activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase. However with DEN treatment, microsomal MDA content and conjugated diene contents were significantly changed. Cytochrome P450 content was also significantly increased while microsomal glucose 6 phophatase activity was significantly decreased with DEN treatment. However activity of NADPH cytochrome P450 reductase was not affected. An interesting finding in this study was that the number and area of hepatic GST P+ foci of the rats fed gamma irradiated beef were significantly(p<0.05) lower than those of the control. Such a lowering effect on GST P+ foci formation was highest at the dose of 3kGy than others. Overall results suggest that the consumption of low dose of gamma irradiated beef does not affect the formation of lipid peroxide, cytochrome P450 system and membrane stability.

• Toxicological Research
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• 제5권1호
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• pp.17-25
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• 1989

Chronic adminstraction of morphine to adult male rats has long been known to lower hepatic cytochrome p-450 content and its dependent mixed-function oxidase activity. Following the treatment of adult male rats with morphine, pethidine pentazocine and codeine and also by concomitant adminstration of naloxone activities of microsomal electron transfer in the adult male rats were examined. In present study, the acute treatment of mature male rats with a dose of narcotic drugs higher than that used chronically also reduces their hepatic cytochrome p-450.

• Fisheries and Aquatic Sciences
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• 제16권4호
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• pp.261-265
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• 2013

The study was conducted to investigate the responses of the hepatic microsomal cytochrome P450 monooxygenase system in the rock bream Oplegnathus fasciatus after chronic exposure to 0, 1, 2, 4, and $8{\mu}g/L$ tributyltin (TBT) concentrations for 4 weeks. Hepatic cytochrome 450 content and ethoxyresorufin O-deethylation (EROD) activity were found to significantly increase in fish treated with the higher concentration of TBT (${\geq}4{\mu}g/L$); however, no significant changes were observed in penthoxyresorufin O-deethylation (PROD) activity in all treated groups compared to the control group. These findings suggest that exposure to a low TBT concentration (${\geq}4{\mu}g/L$) has the potential to induce cytochrome 450 content and EROD enzyme activity in hepatic tissue in the rock bream.

• Journal of Nutrition and Health
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• 제27권5호
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• pp.442-450
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• 1994

The purpose of this study was to determine the effects of 2-AAF injection time on hepatic lipid peroxide metabolism and cytochrome P450 content in Sprague-Dawley rats fed diets containing high amounts of vegetable oils or animal fats(15%, w/w). Fifty mg of 2-AAF/kg of body weight/day was injected in PEG 300 intraperitonially for 3 consecutive days after 4 or 8 weeks to rats fed corn oil(CO) or lard(LA) diet. The contents of lipid peroxide and cytochrome P450, and the activities of superoxide dismutase(SOD), glutathione peroxidase(GSH-peroxidase) and glutathione S-transferase(GSH-S-transferase) were determined in hepatic microsomal or cytosolic fraction. Microsomal thiobarbituric acid reactive substances(TBARS) and cytochrome P450 contents increased in Co group injected 2-AAF after 4weeks. Cytosolic SOD activity increased in CO group injected 2-AAF after 4 weeks and in LA group injected 2-AAF after 4 or 8 weeks. Cytosolic GSH-S-transferase activity increased in LA group compared to CO group without 2-AAF injection. GSH-S-transferase activity increased in CO group injected 2-AAF after 4 or 8 weeks and in LA group injected 2-AAF after 4 weeks. Therefore, it may be suggested that 2-AAF injection increase the contents of lipid peroxide or cytochrome P450, and detoxifying enzyme activities in rats fed CO diet for short period and in rats fed LA diet for longer period.

• Biomolecules & Therapeutics
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• 제2권2호
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• pp.141-148
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• 1994

This study was done to determine whether specific alterations exist in hepatic microsomal function after varying periods of ischemia (IS) and reperfusion (RP) during microsomal lipid peroxidation occurs. Rats were pretreated with $\alpha$-tocopherol to inhibit lipid peroxidation or with vehicle (soybean oil). Control animals were time-matched sham-ischemic animals. Four groups of animals were studied: Group 1 (sham), group 2 (30 mins IS), group 3 (60 mins IS) and group 4 (90 mins IS). After 1, 5 or 24 hr of reperfusion, liver microsomes were isolated and cytochrome P-450s were studied. In all vehicle-treated ischemic rats, serum ALT levels peaked at 5 hr and were significantly reduced by $\alpha$-tocopherol pretreatment. Similarly, microsomal lipid peroxidation was elevated in all vehicle-treated ischemic animal groups, but this elevation was prevented by $\alpha$-tocopherol pretreatment. Cytochrome P-450 content was significantly decreased in both group 3 and group 4. In all vehicle-treated ischemic animal groups, aminopyrine N-demethylase activity was significantly decreased for the entire reperfusion period. $\alpha$-Tocopherol inhibited reductions of cytochrome P-450 content and aminopyrine N-demethylase activity at both 1 hr and 5hr of reperfusion but did not affect the reduced levels of cytochrome P-450 content and aminopyrine N-demethylase activity at 24 hr of reperfusion. Aniline p-hydroxylase activity was significantly decreased in group 4, whereas it was increased in group 3. These decreases and increases were prevented by $\alpha$-tocopherol pretreatment. Our finding suggests that abnormalities in microsomal drug metabolizing function occur during hepatic ischemia and reperfusion in vivo and this is attributed to microsomal lipid peroxidation.

• Archives of Pharmacal Research
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• 제9권2호
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• pp.81-86
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• 1986

The effect of imperatorin on hepatic microsomal mixed function oxidases (MF0) was investigated. On acute treatment, imperatorin (30 mg/kg, i.p) caused a significant reduction in activities of hepatic aminopyrine N-demethylase, hexobarbital hydroxylase and aniline hydroxylase as well as cytochrome p0450 content in rats and mice. Kinetic studies on rat liver enzymes revealed that imperatorin appeared to be a competitive inhibitor of aminopyrine N-demethylase (Ki,0.007 mM), whereas a non-competitive inhibitor of hexobarbital hydroxylase (Ki, 0.0148 mM). Imperatorin also inhibited non-competitively aniline metabolism (Ki 0.2 mM). Imperatorin binds to phenobarbital-induced cytochrome p-450 to give a typical type 1 binding sepctrum (max. 388nm, min 422 nm). Multiple administrations of imperatorin (30 mg/kg. i. p. daily for 7 days) to mice shortended markedly the duration of hexobarbital narcosis and increased activities of hepatic aminopyrine N-demethylase and hexobarbital hydroxylase and the level of cytochrome p-450 where as aniline hydroxylase activity was unaffected.

• Toxicological Research
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• 제11권2호
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• pp.215-221
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• 1995

This paper examines the effects of dietary polyunsaturated fatty acid/saturated fatty acid (p/s) ratios and butylated hydroxytoluene (BHT) on the hepatic microsomaI mixed-function oxidase sy. stem in 2~acetylaminofiuorene (2-AAF) treated rats. Sprague-Dawley male rats were fed the diet of beef tallow (p/s 0.08), beef tallow plus soybean oil (p/s 1.0), and soybean oil (p/s 4.0) at the level of 15%fat and with or without 0.3% BHT. After 2-AAF was injected twice at the ages of 23 and 27 weeks, cholesterol/phospholipid molar ratio, thiobarbituric acid reactive substances (TBARS) level, cytochrome P450, cytochrome $b_5$, NADPH-cytochrome $b_5$, and NADPH-cytochrome c reductase activity were measured from isolated hepatic microsomal fractions. In the beef tallow (p/s 0.08) and beef tallow plus soybean oil (p/s 1.0) groups, cholesterol/phospholipid molar ratio showed decreasing tendency by 2-AAF and BHT. Cytochrome P-450 content was decreased in the group of soybean oil (p/s 4.0) and NADPH-cytochrome c reductase activity was increased by 2-AAF and BHT in all the dietary groups. While TBARS levels were increased by 2-AAF in all the dietary groups, they were reduced by BHT in the soybean oil (p/s 4.0) group. These results suggest that long term intake of soybean oil (p/s 4.0) diet induced changes in the nature of microsomal membrane and induced less cytochrome P-450, low level feeding of BHT increased cytochrome c reductase activity and lowered microsomal lipid peroxidation levels, which were increased by 2-AAF treatment.

• Preventive Nutrition and Food Science
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• 제8권2호
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• pp.158-161
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• 2003

This study investigated the effects of a ${\gamma}$-irradiated pork (0-30 kGy) diet on lipid peroxidation, cytochrome P-450 content, microsomal glucose 6-phosphatase (G-6-Pase) activity and antioxidative defense systems in diethylnitrosamine (DEN)-induced rat hepatocarcinogenesis. The body weight of rats fed irradiated diets did not change significantly. Liver weight was significantly increased by the administration of DEN, but not by irradiated diets at any dose level. There were no significant effects of gamma irradiation on the content of microsomal malondialdehyde (MDA), cytochrome P-450, or on the activity of G-6-Pase. However, with DEN treatment, cytochrome P-450 content was significantly increased while microsomal G-6-Pase activity was significantly decreased. The ${\gamma}$-irradiated diet supplement did not affect serum retinol or $\alpha$-tocopherol concentrations. However, it did cause a significant decrease in hepatic retinol at 30 kGy. With DEN treatment, hepatic retinol content was even more significantly (p<0.05) decreased compared to the non-irradiated control. The enzyme activities related to antioxidative defense systems, including glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Rx) and glutathione S-transferase (GST) were not affected by gamma irradiation. Those results suggest that an irradiated pork diet up to 30 kGy may not cause a health hazard in experimental animals.