Beneficial effects of soy protein consumption on bone quality have been reported. The effects of ... more Beneficial effects of soy protein consumption on bone quality have been reported. The effects of other dietary protein sources such as whey protein hydrolysate (WPH) and rice protein isolate (RPI) on bone growth have been less well examined. The current study compared effects of feeding soy protein isolate (SPI), WPH and RPI for 14 d on tibial bone mineral density
Hepatic cytochrome P450 (CYP)1A1 and 1A2 enzymes were studied in male Sprague-Dawley rats derived... more Hepatic cytochrome P450 (CYP)1A1 and 1A2 enzymes were studied in male Sprague-Dawley rats derived from 5-7 litters fed diets in which the protein source was casein, soy protein isolate or whey. At age 65 d, rats were gavaged with corn oil (vehicle), 40 mg/kg 3-methylcholanthrene (3-MC) or 75 mg/kg isosafrole (ISO). Hepatic expression of CYP1A1 and CYP1A2 mRNA, apoprotein and associated monooxygenase activities were measured 17 h later. No significant dietary effects were observed on basal expression of either enzyme. However, interactions between diet and the two inducers (3-MC and ISO) were observed in soy-fed rats for ethoxy- and methoxyresorufin O-dealkylase activity, CYP1A1 and CYP1A2 apoprotein and mRNA (P < 0.05). The level of induction of CYP1A1 mRNA and apoprotein was lower in rats fed soy diets than in rats fed casein diets (P < 0.05), and the level of induced CYP1A2 mRNA was lower in rats fed soy or whey (P < 0.05) after treatment with the aryl hydrocarbon (Ah) receptor-dependent inducer 3-MC. This was accompanied by a 50% reduction in constitutive levels of the Ah receptor in liver cytosol of soy-fed, relative to casein-fed rats, and a slightly smaller reduction in whey-fed rats. Expression of the Ah receptor correlated with 3-MC-inducibility of CYP1A1 mRNA in rats fed the three diets. In contrast, in rats induced with ISO, which does not bind to the Ah receptor and induces CYP1As via different mechanisms than 3-MC, ethoxyresorufin O-deethylase activity and levels of CYP1A1 apoprotein and mRNA were elevated to a greater degree in soy-fed than in casein- or whey-fed rats (P < 0.05). Moreover, after ISO treatment, induction of methoxyresorufin O-demethylase activity, CYP1A2 apoprotein and mRNA levels was observed only in rats fed soy (P < 0.05). These data suggest potential effects of dietary protein source on metabolism of a wide variety of CYP1A substrates, including environmental and dietary carcinogens, many of which induce their own metabolism.
Journal of Pharmacology and Experimental Therapeutics
The CYP3A subfamily is the most abundant of the human hepatic cytochrome P450 enzymes. They media... more The CYP3A subfamily is the most abundant of the human hepatic cytochrome P450 enzymes. They mediate the biotransformation of many drugs, including a number of psychotropic, cardiac, analgesic, hormonal, immunosuppressant, antineoplastic, and antihistaminic agents. We studied diet/ethanol interactions using total enteral nutrition in adult male Sprague-Dawley rats with diets containing 16% protein, ethanol (13 g/kg), corn oil (fat; 25-45%), and carbohydrate (CHO; 1-21%). Using this model, chronic ethanol feeding decreased CYP3A activity (testosterone 6 beta-hydroxylation) and apoprotein levels (Western blot) (P <.05) and these effects were independent of the dietary CHO/fat ratio. The CYP3A2 mRNA levels decreased (P <.05) in the rats fed ethanol-containing diets by 73 to 83% compared with rats fed control diets, regardless of the CHO/fat ratio. In contrast, ethanol induced CYP3A9 mRNA levels (P <.05) and this effect was greater (P <.05) in the high-CHO/low-fat group (11.3-fold) than in the low-CHO/high-fat group (2.6-fold). Purified recombinant rat P450 3A9 had a chlorzoxazone 6-hydroxylase activity with a turnover number 1.3 nmol/min/nmol of P450. These results indicate that 1) ethanol differentially affects the expression of CYP3A gene family and this regulation appears to be modulated by dietary CHO/fat ratio; 2) the decrease in testosterone 6 beta-hydroxylase activity and CYP3A apoprotein levels are most likely due to the ethanol-induced decrease in CYP3A2 mRNA levels; and 3) CYP3A9 is induced by ethanol and is a low-affinity, high-K(m) chlorzoxazone hydroxylase.
Journal of Pharmacology and Experimental Therapeutics
Ethanol-inducible cytochrome P450 (CYP) 2E1 (CYP2E1) is responsible for the metabolism of many xe... more Ethanol-inducible cytochrome P450 (CYP) 2E1 (CYP2E1) is responsible for the metabolism of many xenobiotics which exert toxic effects in humans. Specific inhibitors might constitute valuable tools in the elucidation of the pharmacological and toxicological roles of this isozyme in vivo. In the present investigation we have evaluated the effects of a drug used for treatment of ethanol withdrawal states, chloromethiazole (CMZ), on CYP2E1 expression in rat liver. A 4-fold induction of CYP2E1 was observed after 3 days of starvation, accompanied by a similar increase in the level of the corresponding mRNA. CMZ specifically inhibited the elevation of CYP2E1 mRNA and protein, but did not prevent CYP2B1 and CYP3A1 or CYP1A1 induction caused by treatment with phenobarbital or beta-naphthoflavone, respectively. From nuclear run-off experiments it was apparent that the rate of the CYP2E1 gene transcription was inhibited greatly by CMZ treatment. Rats treated with ethanol in a total enteral nutrition model had higher CYP2E1-dependent hepatic microsomal activities of p-nitrophenol hydroxylase and carbon tetrachloride-induced lipid peroxidation than controls, and simultaneous CMZ treatment abolished the ethanol-dependent induction. In vitro experiments with rat liver microsomes showed that CMZ did not act as an inhibitor of CYP2E1-dependent catalytic activities or as an inhibitor of microsomal NADPH and CYP2E1-dependent lipid peroxidation. In conclusion, we suggest that CMZ might constitute an efficient and specific inhibitor of CYP2E1 expression suitable for in vivo experiments.
The present study was conducted to determine the effects of two clinically relevant diets on HMO ... more The present study was conducted to determine the effects of two clinically relevant diets on HMO and to determine if ethanol has demonstrable effects in the presence of dietary sources that promote normal growth rates. A model in which ethanol was infused directly into the stomach as part of a total enteral nutrition system (TEN) was used in the current study. The effects of the two liquid diets alone or of TEN where 35% of the total calories in the diets were replaced by ethanol for 8 days were examined on HMO of adult male Sprague-Dawley rats. HMO activities were determined using standard enzyme assays with specific substrates and cytochrome P450 apoprotein levels were determined by Western blot analysis. The results of these studies suggest: that short-term dietary ethanol can induce CYP 2E1 in well nourished animals but that the level of induction is smaller than that previously reported using Lieber-DeCarli pair feeding regimens; that diet alone has a significant influence on c...
Journal of Pharmacology and Experimental Therapeutics
Intragastric infusion of ethanol to male rats as part of a system of total enteral nutrition allo... more Intragastric infusion of ethanol to male rats as part of a system of total enteral nutrition allows chronic ethanol treatment without the nutritional and feeding problems associated with traditional liquid diets. Even though ethanol was infused at a constant rate 24 h a day, blood alcohol concentrations were observed to cycle over a 5- to 7-day period from values less than 10 mg/dl to greater than 400 mg/dl. Examination of the hepatic microsomal mono-oxygenase system in animals chronically treated with ethanol using this model revealed variable induction of cytochrome P450 CYP 2E1, the principal component of the microsomal ethanol oxidizing system. Correlations were observed between urine alcohol concentrations (UACs) and 1) the level of expression of CYP 2E1 mRNA in Northern blot analysis, 2) the level of CYP 2E1 apoprotein in Western blot analysis and, 3) microsomal p-nitrophenol (PNP) hydroxylation. The data from ethanol-treated animals were expressed as low UAC group (UACs < ...
Journal of Pharmacology and Experimental Therapeutics
Growth hormone (GH) secretion is sexually dimorphic in the laboratory rat and the plasma GH profi... more Growth hormone (GH) secretion is sexually dimorphic in the laboratory rat and the plasma GH profile is a determining factor in the regulation of the male-specific cytochrome P450 (CYP) 2C11. Acute ethanol has been reported previously to alter the secretion of GH, and in the present investigation, we have studied the effects of chronic (38 days) ethanol on plasma GH profiles, CYP 2C11 and the major ethanol-inducible cytochrome, CYP 2E1, using a total enteral nutrition system, where 35% of the total calories were ethanol. Ethanol-treated rats had elevated (P < or = .05) CYP 2E1 activities and apoprotein levels and increased steady-state mRNA levels encoding for CYP 2E1. Ethanol-treated rats also had reduced (P < or = .05) hydroxylation of testosterone at positions 2 alpha and 16 alpha, lower 2C11 apoprotein levels and lower steady-state mRNA levels encoding for 2C11. In addition, the plasma GH pulse profiles were altered in chronically treated rats by reducing (P < or = .05) ...
Journal of Pharmacology and Experimental Therapeutics
The current study was conducted to investigate hormonal regulation of cytochrome P450 2C11 (CYP2C... more The current study was conducted to investigate hormonal regulation of cytochrome P450 2C11 (CYP2C11) in rat liver and kidney of adult male rats. In two experiments, hypophysectomy (Hx) resulted in decreased (P < .05) hepatic CYP2C11 apoprotein and mRNA levels. Growth hormone (GH) replacement of Hx rats prevented the decline in hepatic CYP2C11 apoprotein and mRNA levels, whereas, subcutaneous injection of testosterone had no effect. Rat pituitary extract is equally effective in intact or castrated Hx rats in preventing the decline in hepatic CYP2C11 apoprotein and mRNA levels. Specific neutralization of rat GH by sheep anti-rat GH serum reduced (P < . 05) serum IGF-I concentrations, hepatic CYP2C11 apoprotein and mRNA levels. Hx of male rat resulted in decreased (P < .05) renal CYP2C11 apoprotein and mRNA levels, and treatment with GH failed to prevent these effects; however, supplementation of Hx rats with testosterone or rat pituitary extract prevented the Hx-induced decre...
One possible mechanism by which diet may reduce cancer risk is through enhancement of metabolic s... more One possible mechanism by which diet may reduce cancer risk is through enhancement of metabolic systems that prevent activation of carcinogens or accelerate carcinogen inactivation. We studied the effects of diet and 7,12-dimethylbenz-(a)anthracene (DMBA) on hepatic and mammary gland CYP1A1, CYP1A2 and CYP1B1 enzymes in female Sprague-Dawley rats. Diets (AIN-93G) were fed from conception to adulthood, and DMBA was given by oral gavage at age 48-50 d. The protein sources of diets were casein (CAS), soy protein isolate (SPI) or whey protein hydrolysate (WPH). The DMBA-induced hepatic ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase activities and CYP1A1 protein and mRNA expression were lower (P < 0.05) in SPI-fed rats compared with those fed casein. Differences in mammary gland CYP1 expression were also observed with decreased DMBA induction (P < 0.05) of all three CYP1 proteins and mRNAs in rats fed either SPI or WPH compared with those fed CAS. Most notable were...
Hepatic CYP3A enzymes were studied in weanling male Sprague-Dawley rats exposed to diets from ges... more Hepatic CYP3A enzymes were studied in weanling male Sprague-Dawley rats exposed to diets from gestational d 4 in which the sole protein source was either casein (CAS) or soy protein isolate (SPI). At age 25 d, rats were gavaged with corn oil or one of the CYP3A inducers, dexamethasone (DEX) and clotrimazole (CLT), at a dose of 50 mg/kg. Little CYP3A1 (CYP3A23), CYP3A2, or CYP3A9 mRNA was observed in CAS-fed weanling rats but CYP3A18 mRNA was readily detectable in Northern blots. In contrast, consumption of SPI without inducer treatment resulted in the expression of CYP3A1 (CYP3A23), and CYP3A2 mRNAs, expression of CYP3A apoprotein in hepatic microsomes, and a 2-fold greater turnover of the CYP3A substrate midazolam (P < 0.05). DEX induced CYP3A1, CYP3A2, and CYP3A9 (P < 0.05), but not CYP3A18 mRNA expression in rats fed both diets. Hepatic CYP3A apoprotein expression and midazolam 4-hydroxylation in SPI-fed rats was greater than that of CAS-fed rats after DEX treatment (P <...
Effects of intact and processed bovine milk proteins on development of chemically induced mammary... more Effects of intact and processed bovine milk proteins on development of chemically induced mammary tumors in female rats were compared. AIN-93G diets were made with 20% casein (CAS), casein hydrolysate (CASH), intact whey protein (IWP), or whey protein hydrolysate (WPH). Pregnant Sprague-Dawley rats were fed the diets starting at Gestational Day 4. Offspring were fed the same diet. At 50 days, female offspring (44-49/group) were gavaged with sesame oil containing 80 mg/kg of the mammary carcinogen dimethylbenzanthracene (DMBA) and euthanized 62 days posttreatment. Rats fed WPH had an adenocarcinoma incidence of 17% compared to the rats fed CAS, CASH, and IWP diets (34%, 33%, and 36% respectively) (P < 0.001). Median palpable tumor latency for rats fed WPH was greater (61 days, P < 0.001) compared to CAS (44 days), CASH (42 days) and IWP (45 days). Tumor multiplicity was also lower (1.5 vs. 3.0, P < 0.05) in rats fed WPH than in CAS and CASH fed groups. Results demonstrate th...
Background Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidativ... more Background Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidative stress and up-regulates mitochondrial biogenesis. The mechanisms by which chronic EtOH up-regulates mitochondrial biogenesis have not been fully explored. In this work, we hypothesized that oxidative stress is a factor that triggers mitochondrial biogenesis after chronic EtOH feeding. If our hypothesis is correct, co-administration of antioxidants should prevent up-regulation of mitochondrial biogenesis genes.Methods Rats were fed an EtOH-containing diet intragastrically by total enteral nutrition for 150 days, in the absence or presence of the antioxidant N-acetylcysteine (NAC) at 1.7 g/kg/d; control rats were administered isocaloric diets where carbohydrates substituted for EtOH calories.ResultsEtOH administration significantly increased hepatic oxidative stress, evidenced as decreased liver total glutathione and reduced glutathione/glutathione disulfide ratio. These effects were inh...
Chronic ethanol consumption is a prominent cause of liver disease worldwide. Dysregulation of an ... more Chronic ethanol consumption is a prominent cause of liver disease worldwide. Dysregulation of an important lipid uptake and trafficking gene, liver fatty-acid binding protein, may contribute to alterations in lipid homeostasis during early-stage alcoholic liver. We have reported the detrimental effects of ethanol on the expression of L-FABP and hypothesize this may deleteriously impact metabolic networks regulating fatty acids. Male wild-type and L-FABP(-/-) mice were fed a modified Lieber-DeCarli liquid diet for six weeks. To assess the response to chronic ethanol ingestion, standard biochemical indicators for ALD and oxidative stress were measured. Ethanol ingestion resulted in attenuation of hepatic triglyceride accumulation and elevation of cholesterol in L-FABP(-/-) mice. Lipidomics analysis validated multiple alterations in hepatic lipids resulting from ethanol treatment. Increased immunohistochemical staining for the reactive aldehydes 4-hydroxynonenal and malondialdehyde wer...
Bone remodeling is age-dependently regulated and changes dramatically during the course of develo... more Bone remodeling is age-dependently regulated and changes dramatically during the course of development. Progressive accumulation of reactive oxygen species (ROS) has been suspected to be the leading cause of many inflammatory and degenerative diseases, as well as an important factor underlying many effects of aging. In contrast, how reduced ROS signaling regulates inflammation and remodeling in bone remains unknown. Here, we utilized a p47(phox) knock-out mouse model, in which an essential cytosolic co-activator of Nox2 is lost, to characterize bone metabolism at 6 weeks and 2 years of age. Compared with their age-matched wild type controls, loss of Nox2 function in p47(phox) (-/-) mice resulted in age-related switch of bone mass and strength. Differences in bone mass were associated with increased bone formation in 6-week-old p47(phox) (-/-) mice but decreased in 2-year-old p47(phox) (-/-) mice. Despite decreases in ROS generation in bone marrow cells and p47(phox)-Nox2 signaling i...
Beneficial effects of soy protein consumption on bone quality have been reported. The effects of ... more Beneficial effects of soy protein consumption on bone quality have been reported. The effects of other dietary protein sources such as whey protein hydrolysate (WPH) and rice protein isolate (RPI) on bone growth have been less well examined. The current study compared effects of feeding soy protein isolate (SPI), WPH and RPI for 14 d on tibial bone mineral density
Hepatic cytochrome P450 (CYP)1A1 and 1A2 enzymes were studied in male Sprague-Dawley rats derived... more Hepatic cytochrome P450 (CYP)1A1 and 1A2 enzymes were studied in male Sprague-Dawley rats derived from 5-7 litters fed diets in which the protein source was casein, soy protein isolate or whey. At age 65 d, rats were gavaged with corn oil (vehicle), 40 mg/kg 3-methylcholanthrene (3-MC) or 75 mg/kg isosafrole (ISO). Hepatic expression of CYP1A1 and CYP1A2 mRNA, apoprotein and associated monooxygenase activities were measured 17 h later. No significant dietary effects were observed on basal expression of either enzyme. However, interactions between diet and the two inducers (3-MC and ISO) were observed in soy-fed rats for ethoxy- and methoxyresorufin O-dealkylase activity, CYP1A1 and CYP1A2 apoprotein and mRNA (P &lt; 0.05). The level of induction of CYP1A1 mRNA and apoprotein was lower in rats fed soy diets than in rats fed casein diets (P &lt; 0.05), and the level of induced CYP1A2 mRNA was lower in rats fed soy or whey (P &lt; 0.05) after treatment with the aryl hydrocarbon (Ah) receptor-dependent inducer 3-MC. This was accompanied by a 50% reduction in constitutive levels of the Ah receptor in liver cytosol of soy-fed, relative to casein-fed rats, and a slightly smaller reduction in whey-fed rats. Expression of the Ah receptor correlated with 3-MC-inducibility of CYP1A1 mRNA in rats fed the three diets. In contrast, in rats induced with ISO, which does not bind to the Ah receptor and induces CYP1As via different mechanisms than 3-MC, ethoxyresorufin O-deethylase activity and levels of CYP1A1 apoprotein and mRNA were elevated to a greater degree in soy-fed than in casein- or whey-fed rats (P &lt; 0.05). Moreover, after ISO treatment, induction of methoxyresorufin O-demethylase activity, CYP1A2 apoprotein and mRNA levels was observed only in rats fed soy (P &lt; 0.05). These data suggest potential effects of dietary protein source on metabolism of a wide variety of CYP1A substrates, including environmental and dietary carcinogens, many of which induce their own metabolism.
Journal of Pharmacology and Experimental Therapeutics
The CYP3A subfamily is the most abundant of the human hepatic cytochrome P450 enzymes. They media... more The CYP3A subfamily is the most abundant of the human hepatic cytochrome P450 enzymes. They mediate the biotransformation of many drugs, including a number of psychotropic, cardiac, analgesic, hormonal, immunosuppressant, antineoplastic, and antihistaminic agents. We studied diet/ethanol interactions using total enteral nutrition in adult male Sprague-Dawley rats with diets containing 16% protein, ethanol (13 g/kg), corn oil (fat; 25-45%), and carbohydrate (CHO; 1-21%). Using this model, chronic ethanol feeding decreased CYP3A activity (testosterone 6 beta-hydroxylation) and apoprotein levels (Western blot) (P &lt;.05) and these effects were independent of the dietary CHO/fat ratio. The CYP3A2 mRNA levels decreased (P &lt;.05) in the rats fed ethanol-containing diets by 73 to 83% compared with rats fed control diets, regardless of the CHO/fat ratio. In contrast, ethanol induced CYP3A9 mRNA levels (P &lt;.05) and this effect was greater (P &lt;.05) in the high-CHO/low-fat group (11.3-fold) than in the low-CHO/high-fat group (2.6-fold). Purified recombinant rat P450 3A9 had a chlorzoxazone 6-hydroxylase activity with a turnover number 1.3 nmol/min/nmol of P450. These results indicate that 1) ethanol differentially affects the expression of CYP3A gene family and this regulation appears to be modulated by dietary CHO/fat ratio; 2) the decrease in testosterone 6 beta-hydroxylase activity and CYP3A apoprotein levels are most likely due to the ethanol-induced decrease in CYP3A2 mRNA levels; and 3) CYP3A9 is induced by ethanol and is a low-affinity, high-K(m) chlorzoxazone hydroxylase.
Journal of Pharmacology and Experimental Therapeutics
Ethanol-inducible cytochrome P450 (CYP) 2E1 (CYP2E1) is responsible for the metabolism of many xe... more Ethanol-inducible cytochrome P450 (CYP) 2E1 (CYP2E1) is responsible for the metabolism of many xenobiotics which exert toxic effects in humans. Specific inhibitors might constitute valuable tools in the elucidation of the pharmacological and toxicological roles of this isozyme in vivo. In the present investigation we have evaluated the effects of a drug used for treatment of ethanol withdrawal states, chloromethiazole (CMZ), on CYP2E1 expression in rat liver. A 4-fold induction of CYP2E1 was observed after 3 days of starvation, accompanied by a similar increase in the level of the corresponding mRNA. CMZ specifically inhibited the elevation of CYP2E1 mRNA and protein, but did not prevent CYP2B1 and CYP3A1 or CYP1A1 induction caused by treatment with phenobarbital or beta-naphthoflavone, respectively. From nuclear run-off experiments it was apparent that the rate of the CYP2E1 gene transcription was inhibited greatly by CMZ treatment. Rats treated with ethanol in a total enteral nutrition model had higher CYP2E1-dependent hepatic microsomal activities of p-nitrophenol hydroxylase and carbon tetrachloride-induced lipid peroxidation than controls, and simultaneous CMZ treatment abolished the ethanol-dependent induction. In vitro experiments with rat liver microsomes showed that CMZ did not act as an inhibitor of CYP2E1-dependent catalytic activities or as an inhibitor of microsomal NADPH and CYP2E1-dependent lipid peroxidation. In conclusion, we suggest that CMZ might constitute an efficient and specific inhibitor of CYP2E1 expression suitable for in vivo experiments.
The present study was conducted to determine the effects of two clinically relevant diets on HMO ... more The present study was conducted to determine the effects of two clinically relevant diets on HMO and to determine if ethanol has demonstrable effects in the presence of dietary sources that promote normal growth rates. A model in which ethanol was infused directly into the stomach as part of a total enteral nutrition system (TEN) was used in the current study. The effects of the two liquid diets alone or of TEN where 35% of the total calories in the diets were replaced by ethanol for 8 days were examined on HMO of adult male Sprague-Dawley rats. HMO activities were determined using standard enzyme assays with specific substrates and cytochrome P450 apoprotein levels were determined by Western blot analysis. The results of these studies suggest: that short-term dietary ethanol can induce CYP 2E1 in well nourished animals but that the level of induction is smaller than that previously reported using Lieber-DeCarli pair feeding regimens; that diet alone has a significant influence on c...
Journal of Pharmacology and Experimental Therapeutics
Intragastric infusion of ethanol to male rats as part of a system of total enteral nutrition allo... more Intragastric infusion of ethanol to male rats as part of a system of total enteral nutrition allows chronic ethanol treatment without the nutritional and feeding problems associated with traditional liquid diets. Even though ethanol was infused at a constant rate 24 h a day, blood alcohol concentrations were observed to cycle over a 5- to 7-day period from values less than 10 mg/dl to greater than 400 mg/dl. Examination of the hepatic microsomal mono-oxygenase system in animals chronically treated with ethanol using this model revealed variable induction of cytochrome P450 CYP 2E1, the principal component of the microsomal ethanol oxidizing system. Correlations were observed between urine alcohol concentrations (UACs) and 1) the level of expression of CYP 2E1 mRNA in Northern blot analysis, 2) the level of CYP 2E1 apoprotein in Western blot analysis and, 3) microsomal p-nitrophenol (PNP) hydroxylation. The data from ethanol-treated animals were expressed as low UAC group (UACs < ...
Journal of Pharmacology and Experimental Therapeutics
Growth hormone (GH) secretion is sexually dimorphic in the laboratory rat and the plasma GH profi... more Growth hormone (GH) secretion is sexually dimorphic in the laboratory rat and the plasma GH profile is a determining factor in the regulation of the male-specific cytochrome P450 (CYP) 2C11. Acute ethanol has been reported previously to alter the secretion of GH, and in the present investigation, we have studied the effects of chronic (38 days) ethanol on plasma GH profiles, CYP 2C11 and the major ethanol-inducible cytochrome, CYP 2E1, using a total enteral nutrition system, where 35% of the total calories were ethanol. Ethanol-treated rats had elevated (P < or = .05) CYP 2E1 activities and apoprotein levels and increased steady-state mRNA levels encoding for CYP 2E1. Ethanol-treated rats also had reduced (P < or = .05) hydroxylation of testosterone at positions 2 alpha and 16 alpha, lower 2C11 apoprotein levels and lower steady-state mRNA levels encoding for 2C11. In addition, the plasma GH pulse profiles were altered in chronically treated rats by reducing (P < or = .05) ...
Journal of Pharmacology and Experimental Therapeutics
The current study was conducted to investigate hormonal regulation of cytochrome P450 2C11 (CYP2C... more The current study was conducted to investigate hormonal regulation of cytochrome P450 2C11 (CYP2C11) in rat liver and kidney of adult male rats. In two experiments, hypophysectomy (Hx) resulted in decreased (P < .05) hepatic CYP2C11 apoprotein and mRNA levels. Growth hormone (GH) replacement of Hx rats prevented the decline in hepatic CYP2C11 apoprotein and mRNA levels, whereas, subcutaneous injection of testosterone had no effect. Rat pituitary extract is equally effective in intact or castrated Hx rats in preventing the decline in hepatic CYP2C11 apoprotein and mRNA levels. Specific neutralization of rat GH by sheep anti-rat GH serum reduced (P < . 05) serum IGF-I concentrations, hepatic CYP2C11 apoprotein and mRNA levels. Hx of male rat resulted in decreased (P < .05) renal CYP2C11 apoprotein and mRNA levels, and treatment with GH failed to prevent these effects; however, supplementation of Hx rats with testosterone or rat pituitary extract prevented the Hx-induced decre...
One possible mechanism by which diet may reduce cancer risk is through enhancement of metabolic s... more One possible mechanism by which diet may reduce cancer risk is through enhancement of metabolic systems that prevent activation of carcinogens or accelerate carcinogen inactivation. We studied the effects of diet and 7,12-dimethylbenz-(a)anthracene (DMBA) on hepatic and mammary gland CYP1A1, CYP1A2 and CYP1B1 enzymes in female Sprague-Dawley rats. Diets (AIN-93G) were fed from conception to adulthood, and DMBA was given by oral gavage at age 48-50 d. The protein sources of diets were casein (CAS), soy protein isolate (SPI) or whey protein hydrolysate (WPH). The DMBA-induced hepatic ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase activities and CYP1A1 protein and mRNA expression were lower (P < 0.05) in SPI-fed rats compared with those fed casein. Differences in mammary gland CYP1 expression were also observed with decreased DMBA induction (P < 0.05) of all three CYP1 proteins and mRNAs in rats fed either SPI or WPH compared with those fed CAS. Most notable were...
Hepatic CYP3A enzymes were studied in weanling male Sprague-Dawley rats exposed to diets from ges... more Hepatic CYP3A enzymes were studied in weanling male Sprague-Dawley rats exposed to diets from gestational d 4 in which the sole protein source was either casein (CAS) or soy protein isolate (SPI). At age 25 d, rats were gavaged with corn oil or one of the CYP3A inducers, dexamethasone (DEX) and clotrimazole (CLT), at a dose of 50 mg/kg. Little CYP3A1 (CYP3A23), CYP3A2, or CYP3A9 mRNA was observed in CAS-fed weanling rats but CYP3A18 mRNA was readily detectable in Northern blots. In contrast, consumption of SPI without inducer treatment resulted in the expression of CYP3A1 (CYP3A23), and CYP3A2 mRNAs, expression of CYP3A apoprotein in hepatic microsomes, and a 2-fold greater turnover of the CYP3A substrate midazolam (P < 0.05). DEX induced CYP3A1, CYP3A2, and CYP3A9 (P < 0.05), but not CYP3A18 mRNA expression in rats fed both diets. Hepatic CYP3A apoprotein expression and midazolam 4-hydroxylation in SPI-fed rats was greater than that of CAS-fed rats after DEX treatment (P <...
Effects of intact and processed bovine milk proteins on development of chemically induced mammary... more Effects of intact and processed bovine milk proteins on development of chemically induced mammary tumors in female rats were compared. AIN-93G diets were made with 20% casein (CAS), casein hydrolysate (CASH), intact whey protein (IWP), or whey protein hydrolysate (WPH). Pregnant Sprague-Dawley rats were fed the diets starting at Gestational Day 4. Offspring were fed the same diet. At 50 days, female offspring (44-49/group) were gavaged with sesame oil containing 80 mg/kg of the mammary carcinogen dimethylbenzanthracene (DMBA) and euthanized 62 days posttreatment. Rats fed WPH had an adenocarcinoma incidence of 17% compared to the rats fed CAS, CASH, and IWP diets (34%, 33%, and 36% respectively) (P < 0.001). Median palpable tumor latency for rats fed WPH was greater (61 days, P < 0.001) compared to CAS (44 days), CASH (42 days) and IWP (45 days). Tumor multiplicity was also lower (1.5 vs. 3.0, P < 0.05) in rats fed WPH than in CAS and CASH fed groups. Results demonstrate th...
Background Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidativ... more Background Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidative stress and up-regulates mitochondrial biogenesis. The mechanisms by which chronic EtOH up-regulates mitochondrial biogenesis have not been fully explored. In this work, we hypothesized that oxidative stress is a factor that triggers mitochondrial biogenesis after chronic EtOH feeding. If our hypothesis is correct, co-administration of antioxidants should prevent up-regulation of mitochondrial biogenesis genes.Methods Rats were fed an EtOH-containing diet intragastrically by total enteral nutrition for 150 days, in the absence or presence of the antioxidant N-acetylcysteine (NAC) at 1.7 g/kg/d; control rats were administered isocaloric diets where carbohydrates substituted for EtOH calories.ResultsEtOH administration significantly increased hepatic oxidative stress, evidenced as decreased liver total glutathione and reduced glutathione/glutathione disulfide ratio. These effects were inh...
Chronic ethanol consumption is a prominent cause of liver disease worldwide. Dysregulation of an ... more Chronic ethanol consumption is a prominent cause of liver disease worldwide. Dysregulation of an important lipid uptake and trafficking gene, liver fatty-acid binding protein, may contribute to alterations in lipid homeostasis during early-stage alcoholic liver. We have reported the detrimental effects of ethanol on the expression of L-FABP and hypothesize this may deleteriously impact metabolic networks regulating fatty acids. Male wild-type and L-FABP(-/-) mice were fed a modified Lieber-DeCarli liquid diet for six weeks. To assess the response to chronic ethanol ingestion, standard biochemical indicators for ALD and oxidative stress were measured. Ethanol ingestion resulted in attenuation of hepatic triglyceride accumulation and elevation of cholesterol in L-FABP(-/-) mice. Lipidomics analysis validated multiple alterations in hepatic lipids resulting from ethanol treatment. Increased immunohistochemical staining for the reactive aldehydes 4-hydroxynonenal and malondialdehyde wer...
Bone remodeling is age-dependently regulated and changes dramatically during the course of develo... more Bone remodeling is age-dependently regulated and changes dramatically during the course of development. Progressive accumulation of reactive oxygen species (ROS) has been suspected to be the leading cause of many inflammatory and degenerative diseases, as well as an important factor underlying many effects of aging. In contrast, how reduced ROS signaling regulates inflammation and remodeling in bone remains unknown. Here, we utilized a p47(phox) knock-out mouse model, in which an essential cytosolic co-activator of Nox2 is lost, to characterize bone metabolism at 6 weeks and 2 years of age. Compared with their age-matched wild type controls, loss of Nox2 function in p47(phox) (-/-) mice resulted in age-related switch of bone mass and strength. Differences in bone mass were associated with increased bone formation in 6-week-old p47(phox) (-/-) mice but decreased in 2-year-old p47(phox) (-/-) mice. Despite decreases in ROS generation in bone marrow cells and p47(phox)-Nox2 signaling i...
Uploads
Papers