Biotransformation of territrems by S9 fraction from rat liver

Male Wistar rats were pretreated with phenobarbital, 3-methyl-cholanthrene, or polychlorinated biphenyl. The S9 fraction was isolated from their livers. An amount of 40-microliters territrem (TRA, B, or C) (1 mg/ml methanol) was added to 5-ml reaction mixtures containing S9 (8 mg protein), NADP sodium salt (20 mumol), glucose-6-phosphate monosodium salt (25 mumol), MgCl2 (40 mumol), KCl (165 mumol), and sodium phosphate buffer, 0.1 M, pH 7.4, after preincubation for 5 min. Further incubation was carried out for 30 min by shaking (100 ocillations/min). The reaction was stopped by adding 2 ml acetone. The acetone was then removed by evaporation in a hood at room temperature. The residue was lyophilized and extracted with 2 ml methanol 3 times. When TRB was a substrate, at least four blue fluorescent products, designated as MB1, MB2, MB3, and MB4, were found in the methanol extract by TLC under view of long-wave UV light. MB2 was the major product. When TRA or TRC was a substrate, two products, MA1 (the major product) and MA2 from TRA, and one product, MC from TRC, were, respectively, detected in the methanol extract. The formation of the products was dependent on the presence of S9, NADP, glucose-6-phosphate, and territrem. The reaction was enhanced by pretreatment of rats with phenobarbital. It was demonstrated that MB2 and MA1 are hydroxylated products of the methyl group at the C4 position of TRB and TRA. MB4 was identified as TRC. MC was shown to be identical to MB1, which was the hydroxylated product at the methyl group of C4 position of TRC.(ABSTRACT TRUNCATED AT 250 WORDS)