Activation and Degradation Efficiencies of Liver Microsomes from Eight Vertebrate Species, Using Organophosphates as Substrates1

Abstract

The capacity of liver microsomes from 8 vertebrate species, chickens, Gallus domesticus L.; Muscovy ducks, Cairima moschala Phillips; albino rats, Rattus norvegicus (Berkenhout); mice, Mus musculus L.; guinea pigs, Cavia Porcellus L.; sheep, Ovis aries L.; cattle, Bos taurus L.; and hogs, Suisscrota domestica, L., to activate methyl parathion and azinphosmethyl was studied. Degradation of their respective P (0) analogs was examined to determine the effects of degradation on net activation. Sexual differences were also studied. Activation or degradation of the organophosphates was determined by manometric, anticholinesterase assays of their incubation products, using house fly, Musca domestica L., head cholinesterase. In general, microsomal enzymes with a high activation effect had a comparatively low degradative effect and vice versa. Activation and degradation were both more extensive with azinphosmethyl than with methyl parathion. Several sharp differences in activation and degradation of these organophosphates were found, both between species and sexes.