PT  - JOURNAL ARTICLE
AU  - H. B. MATTHEWS
AU  - J. D. MCKINNEY
TI  - DIELDRIN METABOLISM TO <em>CIS</em>-DIHYDROALDRINDIOL AND
EPIMERIZATION OF <em>CIS</em>- TO <em>TRANS</em>-DIHYDROALDRINDIOL
BY RAT LIVER MICROSOMES
DP  - 1974 Jul 01
TA  - Drug Metabolism and Disposition
PG  - 333--340
VI  - 2
IP  - 4
4099  - http://dmd.aspetjournals.org/content/2/4/333.short
4100  - http://dmd.aspetjournals.org/content/2/4/333.full
SO  - Drug Metab Dispos1974 Jul 01; 2
AB  - In contrast to previous reports, cis-dihydroaldrindiol, as well as the trans-isomer, has been shown to be formed in vitro from dieldrin in rat liver preparations. Further, an enzyme in the same fraction of rat liver homogenate has been shown to rapidly epimerize synthetic cis-dihydroaldrindiol to the trans-isomer in vitro. The epimerase is located in the microsomes and requires NADPH and cytochrome P-450, but does not require molecular oxygen. Thus, it apparently utilizes a portion of the mixed-function oxidase electron transfer chain, but cannot be considered a mixed-function oxidase. The existence of such an epimerase in close association with the enzyme responsible for the oxidation of cyclic hydrocarbons may explain the stereochemical configuration of the dihydrodiol metabolite of dieldrin, and possibly other cyclic hydrocarbons, excreted by mammals. Copyright © 1974 by The American Society for Pharmacology and Experimental Therapeutics