The author started a research on
xenobiotic metabolism at Graduate School of
Pharmaceutical Sciences, Kyushu University in 1965. In 1968, an epidemic of a "strange disease", called Yusho, occurred in western Japan. The epidemic was soon identified to be a
food poisoning caused by the ingestion of commercial Kanemi
rice bran oil which had been accidentally contaminated with large amounts of
polychlorinated biphenyls (
PCBs) and their related compounds such as
polychlorinated dibenzofurans (PCDFs.) At first, in this review, our toxicological studies on Yusho during the early thirty years were briefly described. Next, the studies on
aldehyde oxidase, a
molybdenum hydroxylase, which is involved in the
lactam formation reaction such as 1-phenyl-2-(2-oxopyrrolidine)pentane(oxoprolintane) from 1-phenyl-2-pyrrolidinopentane(prolintane) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)
lactam from
1-methyl-4-phenyl-2,3-dihydropyridinium ion (MPDP⁺) were also presented. Finally, we investigated how the
xenobiotic metabolism of
endocrine disrupting chemicals such as
bisphenol A (BPA) and some
isoflavones affects their estrogenic activities. In this study, we demonstrated that BPA is converted to
4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), an active metabolite as
estrogen, by rat liver S9. In the cases of
isoflavones, although
genistein was inactivated,
biochanin A, 4'-methoxy analogue of
genistein, was activated to
genistein by O-demethylation with rat liver S9.