Zhang L, Kasai S, Shono T
Laboratory of Applied Zoology, Institute of Agriculture and Forestry, University of Tsukuba, Ibaraki, Japan.
Arch Insect Biochem Physiol. 1998;37(3):215-24. doi: 10.1002/(SICI)1520-6327(1998)37:3<215::AID-ARCH4>3.0.CO;2-R.
Levels of cytochrome P450 and b5 were investigated in microsomal enzymes of houseflies from the gut and fat body of the third instar larvae of a pyriproxyfen-resistant strain (YPPF) and two pyriproxyfen-susceptible strains (YS and SRS). In comparison to the YS and SRS strains, YPPF microsomes had higher levels of total cytochrome P450s in both the gut and fat body. Furthermore, microsomes from the gut and fat body of YPPF larvae were found to have a much greater ability to hydroxylate aniline than YS larvae. In vitro metabolism studies of pyriproxyfen indicated that the metabolic rates were much higher in both the gut and fat body of YPPF larvae than of YS and SRS larvae. The major metabolites of pyriproxyfen in houseflies were identified to be 4'-OH-pyriproxyfen and 5"-OH-pyriproxyfen. Cytochrome P450 inhibitors, piperonyl butoxide (PB) and 2-propynyl 2,3,6-trichlorophenyl ether (PTPE), decreased the metabolic rates significantly in all three strains. This study confirmed that microsomal cytochrome P450 monooxygenases play an important role in the pyriproxyfen resistance of the housefly. Furthermore, it suggests that the fat body must be as important as the gut for the metabolism of pyriproxyfen in resistant housefly larvae.
研究了抗吡丙醚品系（YPPF）以及两个吡丙醚敏感品系（YS和SRS）三龄幼虫肠道和脂肪体中家蝇微粒体酶中细胞色素P450和b5的水平。与YS和SRS品系相比，YPPF微粒体在肠道和脂肪体中的总细胞色素P450水平更高。此外，发现YPPF幼虫肠道和脂肪体的微粒体比YS幼虫具有更强的苯胺羟基化能力。吡丙醚的体外代谢研究表明，YPPF幼虫肠道和脂肪体中的代谢率均远高于YS和SRS幼虫。家蝇中吡丙醚的主要代谢产物被鉴定为4'-羟基吡丙醚和5''-羟基吡丙醚。细胞色素P450抑制剂胡椒基丁醚（PB）和2-丙炔基2,3,6-三氯苯醚（PTPE）显著降低了所有三个品系的代谢率。本研究证实微粒体细胞色素P450单加氧酶在家蝇对吡丙醚的抗性中起重要作用。此外，这表明在抗性家蝇幼虫中，脂肪体对于吡丙醚的代谢与肠道同样重要。
