Separation and purification of liver microsomal monooxygenases from induced and untreated pigs

From liver microsomes of phenobarbital-, beta-naphthoflavone- and ethanol-pretreated male pigs and of controls NADPH-cytochrome P-450 reductase and four cytochrome P-450 fractions were isolated according to a modified procedure of Imai and Sato. Electrophoretic, immunological, spectral and catalytic properties suggested that at least five different forms of cytochrome P-450 could be separated, two of which were obtained in a pure state. Using selective inhibitors and antisera it was concluded that microsomes from phenobarbital-pretreated pigs contain at least three forms which all were metyrapone-sensitive. beta-Naphthoflavone induced probably two 7,8-benzoflavone-sensitive forms. After ethanol administration the main form of cytochrome P-450 was identical to that of controls.