DISTRIBUTION OF ABCG2 (BCRP) AND ABCC2 (MRP2) MRNAS IN RAT SMALL INTESTINE AND LIVER

The purpose of this study is to examine the distribution of Abcg2 and Abcc2 mRNAs in the intestine and liver of male Wistar rats, and any regional differences. Nine-week-old male rats were used, and their intestine divided equally into nine segments. The expression patterns of Abcg2 and Abcc2 mRNAs in the intestine and liver were examined using a reverse transcription-polymerase chain reaction (RT-PCR). PCR products for Abcg2 mRNA were readily detectable in the intestine, but no bands were detected in the liver. In addition, the level of Abcg2 mRNA increased significantly from the duodenum to ileum, indicating a regional difference in Abcg2 mRNA expression in the intestine. This regional difference was comparable to that of Abcb1/mdr1a as reported previously. On the other hand, Abcc2 mRNA was detected at a higher level in the liver than in the intestine. However, there was no regional difference in Abcc2 mRNA expression in the intestine. Collectively, Abcg2 was predominant in the intestine rather than liver in male Wistar rats, whereas Abcc2 was predominant in the liver. These findings will provide useful information for evaluating the gastrointestinal secretion of drugs as well as drug-drug interactions in rats.