Purification and characterization of dexamethasone inducible hepatic cytochrome P450 isozymes from rhesus monkey.

Two isozymes of hepatic cytochrome P450 named DEX M-1 and M-2 have been purified and characterized from dexamethasone (DEX) pretreated (150 mg Kg-1 body wt x 4 days) rhesus monkeys by various chromatographic procedures. These isozymes demonstrated similar peptide maps. Their absolute and CO-dithionite reduced difference spectra demonstrated maximum absorbance at 417 and 449.4 nm, respectively. DEX M-1 and M-2 demonstrated polypeptide molecular wt of 50 and 52.5 KDa, specific content of 16.35 and 11.39 nmol mg-1 protein and 11 and 8 fold purification, respectively. The antibodies against these isozymes cross reacted with each other and also demonstrated slight differences in the immunoinhibition of erythromycin N-demethylase. These results demonstrated that DEX induced two different isozymes of hepatic cytochrome P450 in rhesus monkeys.