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KMID : 0385219970070020029
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Korean Journal of Gerontology
1997 Volume.7 No. 2 p.29 ~ p.36
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Effect of Food Restriction on Age-related Changes of Liver Microsomal Cytochrome p-450 System
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Lim Heung-Bin
Sohn Hyung-Ok
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Abstract
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Microsomal mixed function oxidase (MFO) activity is altered by both intrinsic and extrinsic factors such as environments. Age-related changes in liver microsomal xenobiotic metabolizing enzymes by a 40% food restriction were investigated in rats reared in an open barriers facility. The contents of cytochrome P-450 and cytochrome b5, the activity of cytochrome P-450 reductase were decreased in an age-dependent manner in liver microsome of rats fed both ad. libitum fed (AL) rats and food restricted (FR) rats. The specific activity of cytochrome b5 reductase in 12 month old rats was lower than in 6 and 24 month old rats, however, decreases in the activities of these microsomal enzymes were effectively attenuated by food restriction. Liver microsomal P-450dependent ethoxycoumarin O-deethylase and benzphetamine N-demethylase activities were also decreased in an age-dependent manner in both AL and FR rats. Microsomal testosterone 16 α-, testosterone 6 β- and testosterone 2 α-hydroxylase activities in AL rats were also significantly decreased with age in a similar manner to ECOD and BPDM activities and their age-related decline was attenuated by food restriction. However, the activities of teatosterone 7 α-and testosterone 16 β-hydroxylase were maintained during senescence in both groups. The activity of glutathione-s-transferase, one of phase II xenobiotic-metabolizing enzymes, was also declined in an age-dependent manner in AL rats, but unlike FR rats, there was no significant change with age. The results suggest that food restriction attenuates the age-related decrease in activities of liver microsomal phase I and phase II enzymes in rats reared in an open barrier facility.
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KEYWORD
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Aging, Food restriction, Cytochrome P-450, Xenobiotic metabolizing enzymes
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