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

Hepatic microsomal estrogen metabolism was analyzed in the (New Zealand black × New Zealand white)F₁ ([NZB × 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 × 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 16α-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 × NZW)F₁ mice in a manner that would result in abnormal retention of hormonally active metabolites.