Effect of Carbon Monoxide on Metabolism of Insecticides in vivo

Abstract

THERE have recently been several reports which indicate that the oxidative metabolism of drugs by liver microsomes involves a eytoehrome-like pigment usually referred to as P-450 (refs, 1 and 2). This pigment, which is characterized by the difference spectrum observed when microsomal suspensions reduced either with hydrosulphite or with NADPH are saturated with carbon monoxide, has recently been found in microsomes from the housefly Musca domestica (vicina strain)³. Furthermore, the inhibition by carbon monoxide of the epoxidation of aldrin and the partial reversal of this inhibition by light supports the view that P-450 is involved in epoxidation by fly microsomes in vitro. Similar evidence has been produced to support the view that this pigment is involved in the metabolism of drugs by microsomes from rat liver². Evidence for the role of a reaction in the metabolism of insecticides in vivo which is sensitive to carbon monoxide has not, however, been reported.