Figure 2

Canalicular efflux expression in liver of db/db and C57BKS mice. A) Messenger RNA expression for Abcc2, Abcg2, Abcb11 and Abcb1. Total RNA was isolated from liver, and mRNA was quantified using branched DNA signal amplification assay. The data plotted as average Relative Light Unit (RLU) per 10 μg total RNA ± SEM. Asterisks (*) represent a statistically significant expression difference between C57BKS and db/db mice of same gender (p≤0.05). Number signs (#) represent a statistically significant expression gender difference between male and female db/db mice, or male and female C57BKS mice. B) Abcc2 and Abcg2 protein identification and quantification by western blot in crude membrane fractions from livers of C57BKS and db/db mice. Proteins (75μg/lane) were separated on 4–20% acrylamide/PAGE, transblotted, incubated with primary and secondary antibodies, and visualized by fluorescence. C) Quantification of western blots by using the Quantity One® software (Biorad, Hercules, CA). The average band intensity for C57BKS males was considered 100% and other groups were compared with that density. Asterisks (*) represent a statistically significant difference between average band intensity as compared to that of C57BKS males (p≤0.05). Abcc2 mRNA expression increased in both male and female db/db mice, whereas protein expression increased in db/db males as compared to respective controls. In db/db females, both mRNA and protein expression of Abcg2 was upregulated, and in db/db males, Abcg2 mRNA was not significantly upregulated but the protein was significantly up. Abcb11 and Abcb1 mRNA expression was down in db/db females as compared to C57BKS females.