ABSTRACT: Knowing the gene expression profiles of drug-metabolizing enzymes and transporters throughout gestation is important for understanding the mechanisms of pregnancy-induced changes in drug pharmacokinetics. In this study, we compared gene expression of drug-metabolizing enzymes and transporters in the maternal liver, kidney, small intestine, and placenta of pregnant mice throughout gestation by microarray analysis. Specifically, we investigated cytochrome P450 (Cyp), UDP-glucuronosyltranserase (Ugt), and sulfotransferase (Sult), as well as ATP-binding cassette (Abc) and solute carrier (Slc) transporters. We found that relatively few Ugt and Sult genes were impacted by pregnancy in maternal tissues and placenta. Cyp1a2, most Cyp2 isoforms, Cyp3a11, and Cyp3a13 in the liver were down-regulated, with the greatest changes occurring on gestation days (gd) 15 and 19 compared to non-pregnant controls (gd 0). However, Cyp2d40, Cyp3a16, Cyp3a41a, Cyp3a41b, and Cyp3a44 in the liver were induced throughout pregnancy. Cyp expression in mid-gestation placenta (gd 10 and 15) was generally greater than that in term placenta (gd 19). There were also notable changes in Abc and Slc transporters. Abcc3 in the liver was down-regulated by 60%, and Abcb1a, Abcc4, and Slco4c1 in the kidney were down-regulated by 30-60% on gd 15 and 19 versus gd 0. Abcc5 in the placenta was induced 3-fold on gd 10 versus gd 15 and 19, whereas Slc22a3 expression in the placenta on gd 10 was 90% lower than that on gd 15 and 19. Overall, this study demonstrates important gestational age-dependent expression of drug-metabolizing enzymes and transporter genes, which may have mechanistic relevance to human pregnancy. Ninety pregnant mice at gestational days 0, 7.5, 10, 15, and 19 (n = 5-6 per gestational age) were used for the maternal liver, kidney, small intestine and placenta. The placentas were collected on gestational days 10, 15, and 19.
