Incubation solutions containing 10 μM of eprinomectin and 0.5 mg/ml microsomal protein were incubated for 45 min at 37°C. Microsomes were preincubated with inhibitors at 37°C for 10 min before the reaction was initiated by the addition of eprinomectin. Percentage of control is the percentage of eprinomectin metabolized in the presence of inhibitor relative to control samples that had no inhibitor. Each point represents an average of duplicates.