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J Occup Health year 2005 volume 47 number 1 page 49 - 55
Classification Original
Title Effects of Pregnancy, Age and Sex in the Metabolism of Styrene in Rat Liver in Relation to the Regulation of Cytochrome P450 Enzymes
Author Reiko KISHI1, Fumihiro SATA1, Yoko KATAKURA1, Rui-Sheng WANG2 and Tamie NAKAJIMA3
Organization 1Department of Public Health, Hokkaido University Graduate School of Medicine, 2Department of Hazard Assessment, National Institute of Industrial Health and 3Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Japan
Keywords Styrene, Metabolism, Cytochrome P450, Liver, Pregnancy, Rats
Correspondence R. Kishi, Department of Public Health, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan
(e-mail: rkishi@med.hokudai.ac.jp)
Abstract Effects of Pregnancy, Age and Sex in the Metabolism of Styrene in Rat Liver in Relation to the Regulation of Cytochrome P450 Enzymes: Reiko KISHI, et al. Department of Public Health, Hokkaido University Graduate School of Medicine-To elucidate the effect of maternal styrene exposure, which is due to various postnatal changes in the development and behavior of offspring, we investigated pregnancy-induced changes in the metabolism of styrene in rat liver in relation to the regulation of cytochrome P450 enzymes. We also examined age and sex-induced changes in the metabolism of styrene. Pregnancy appeared to exert a negative effect on cytochrome P450 content at the late stage, whereas microsomal protein content showed little change during pregnancy. Pregnancy significantly decreased the rate of formation of styrene glycol at the late stage. The percentage of remaining activity in microsomes exposed to anti-CYP2E1 was lower than that exposed to anti-CYP2C11/6 in pregnant and non-pregnant female rats and immature male rats, indicating that CYP2E1 contributes to the metabolism of styrene more than CYP2C11/6 in these rats. Although pregnancy seemed to decrease styrene metabolism, the contribution of CYP2E1 seemed to be slightly increasing. In conclusion, pregnancy clearly influences the metabolism of styrene as well as other characteristic factors such as age and sex. It is very important to elucidate the changes in specific P450 isozyme composition related to their characteristic modification and in their affinity for chemicals.