The effects of ethyl eicosapentaenoate (EPA-E) and docosahexaenoic acid (DHA) on the rat hepatic drug and fatty acid metabolizing enzyme systems were studied after single or repeated oral administration for 14 d. The ratio of liver to body weight and protein concentration in each fraction of microsomes, mitochondria and peroxisomes were not affected after single or repeated administration of EPA-E or DHA. Neither induction nor inhibition of hepatic drug metabolizing enzymes was not observed in EPA-E group. A single administration of DHA decreased aniline p-hydroxylase activity. This decrease in activity, however, was neither enhanced nor reduced after repeated administration of DHA. Other hepatic drug metabolizing enzymes were not affected by DHA. No effects on fatty acid oxidizing enzyme systems of mitochondria and peroxisomes were observed after administration of EPA-E or DHA. No effects on fatty acid elongation and desaturation on microsomes were observed after administration of EPA-E or DHA.
