Fig. 2.

Regulation of the UGT1 locus during pregnancy. (A) Serum bilirubin levels in female hUGT1*28 mice were determined before pregnancy and at GD18 (*P < 0.05, Student's t test). (B) Quantitation of liver UGT1A gene expression by RT and Q-PCR in adult female and male mice. The relative values are expressed as a ratio value comparing female to male expression. (C) Quantitation of liver UGT1A gene expression in hUGT1*1 mice pregnant for 16 days. Total liver RNA was prepared and used in RT and Q-PCR analysis with specific UGT1A gene oligonucleotides. Fold induction was calculated relative to those values obtained in nonpregnant mice. (D) Immunoblot analysis of human UGT expression in nonpregnant and pregnant hUGT1*1 mice. Microsomes were prepared from nonpregnant and pregnant hUGT1*1 mice and subjected to 4%-12% polyacrylamide gel electrophoresis. Following blotting, protein expression was determined using a UGT1A antibody, or isozyme specific UGT1A1, UGT1A4, and UGT1A6 antibodies.