Aminopyrine N-demethylation in young, old and tumour bearing B6C3 F1 mice

Estrogen metabolism in the (New Zealand black x New Zealand white)F1 murine model of systemic lupus erythematosus

Hepatic microsomal estrogen metabolism was analyzed in the (New Zealand black x New Zealand white)F1 ([NZB x NZW]F1) murine model of systemic lupus erythematosus. Both the estrogen 2-hydroxylase activity (per mg microsomal protein) and the hepatic cytochrome P-450 content were higher in premorbid (NZB x NZW)F1 mice, as compared with similarly aged nonautoimmune mice. However, these differences were not associated with alterations in the relative formation of the 2-hydroxylated and the 16 alpha-hydroxylated metabolites. The development of overt nephritis was associated with a decrease in estrogen metabolic activity, but not with any alteration in the distribution of estrogen metabolites. Thus, estrogen metabolism was not altered in premorbid (NZB x NZW)F1 mice in a manner that would result in abnormal retention of hormonally active metabolites.