Developmental changes of microsomal cytochrome [formula omitted] monooxygenases in larval and adult Diploptera punctata

Abstract

The changes in several microsomal cytochrome P-450 monooxygenases were followed in fat body and midgut of the cockroach, Diploptera punctata, during the last larval stage and during the adult stage. The specific activities of aldrin epoxidation, 7-methoxy-4-methylcoumarin O- demethylation and NADPH-cytochrome c reductase were higher in the midgut than in the fat body, but the specific activity of methoxyresorufin O- demethylation was higher in the fat body. The specific activities were low at the time of ecdysis, but the developmental patterns during the last larval stage and during the adult stage were different for the fat body and the midgut enzyme activities, suggesting independent control mechanisms. In the midgut of adults, the various enzyme activities were similar between virgin females and mated females, thus ruling out a possible relation with the gonotrophic cycle which is controlled by juvenile hormone. Significant differences were observed between midgut enzyme activities of male and female roaches. Enzyme levels were drastically reduced in midguts of starved insects, but were restored upon feeding. Our results suggest that the developmental changes of cytochrome P-450 monooxygenases are specific for sex, tissue and possibly also isozymic form of cytochrome P-450.