Sangeet Honey , Patrick O’Keefe , Adam T. Drahushuk , James R. Olson , Subodh Kumar , Harish C. Sikka
{"title":"Metabolism of benzo(a)pyrene by duck liver microsomes","authors":"Sangeet Honey , Patrick O’Keefe , Adam T. Drahushuk , James R. Olson , Subodh Kumar , Harish C. Sikka","doi":"10.1016/S0742-8413(00)00121-3","DOIUrl":null,"url":null,"abstract":"<div><p>The metabolism of benzo(a)pyrene [BP], a model carcinogenic PAH, by hepatic microsomes of two duck species, mallard (<em>Anas platyrhynchos</em>) and common merganser (<em>Mergus merganser americanus</em>) collected from chemically-contaminated and relatively non-contaminated areas was investigated. The rate of metabolism of BP by liver microsomes of common merganser and mallard collected from polluted areas (2650±310 and 2200±310 pmol/min per mg microsomal protein, respectively) was significantly higher than that obtained with liver microsomes of the two species collected from non-polluted areas (334±33 and 231±30 pmol/min per mg microsomal protein, respectively). The level of cytochrome P-450 1A1 was significantly higher in the liver microsomes of both duck species from the polluted areas as compared to the ducks from the non-polluted areas. The major BP metabolites, including BP-9, 10-diol, BP-4, 5-diol, BP-7, 8-diol, BP-1, 6-dione, BP-3, 6-dione, BP-6, 12-dione, 9-hydroxy-BP and 3-hydroxy-BP, formed by liver microsomes of both duck species from polluted and non-polluted areas, were qualitatively similar. However, the patterns of these metabolites were considerably different from each other. Liver microsomes of ducks from the polluted areas produced a higher proportion of benzo-ring dihydrodiols than the liver microsomes of ducks from the non-polluted areas, which converted a greater proportion of BP to BP-phenols. The predominant enantiomer of BP-7,8-diol formed by hepatic microsomes of the two duck species had an (−)<em>R</em>,<em>R</em> absolute stereochemistry. The data suggest that duck and rat liver microsomal enzymes have different regioselectivity but similar stereoselectivity in the metabolism of BP.</p></div>","PeriodicalId":10586,"journal":{"name":"Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2000-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0742-8413(00)00121-3","citationCount":"17","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0742841300001213","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 17
Abstract
The metabolism of benzo(a)pyrene [BP], a model carcinogenic PAH, by hepatic microsomes of two duck species, mallard (Anas platyrhynchos) and common merganser (Mergus merganser americanus) collected from chemically-contaminated and relatively non-contaminated areas was investigated. The rate of metabolism of BP by liver microsomes of common merganser and mallard collected from polluted areas (2650±310 and 2200±310 pmol/min per mg microsomal protein, respectively) was significantly higher than that obtained with liver microsomes of the two species collected from non-polluted areas (334±33 and 231±30 pmol/min per mg microsomal protein, respectively). The level of cytochrome P-450 1A1 was significantly higher in the liver microsomes of both duck species from the polluted areas as compared to the ducks from the non-polluted areas. The major BP metabolites, including BP-9, 10-diol, BP-4, 5-diol, BP-7, 8-diol, BP-1, 6-dione, BP-3, 6-dione, BP-6, 12-dione, 9-hydroxy-BP and 3-hydroxy-BP, formed by liver microsomes of both duck species from polluted and non-polluted areas, were qualitatively similar. However, the patterns of these metabolites were considerably different from each other. Liver microsomes of ducks from the polluted areas produced a higher proportion of benzo-ring dihydrodiols than the liver microsomes of ducks from the non-polluted areas, which converted a greater proportion of BP to BP-phenols. The predominant enantiomer of BP-7,8-diol formed by hepatic microsomes of the two duck species had an (−)R,R absolute stereochemistry. The data suggest that duck and rat liver microsomal enzymes have different regioselectivity but similar stereoselectivity in the metabolism of BP.