Efflux transporter expression in kidneys of C57BKS and db/db mice. A) Messenger RNA expression of Abcc3, 4 and Abcb1. Total RNA was isolated from kidneys of adult db/db and C57BKS mice, and mRNA expression was quantified using the branched DNA signal amplification assay. The data plotted as average RLU per 10 μg total RNA ± SEM. B) Protein expression of Abcc4 from crude membrane fractions of kidneys of C57BKS and db/db mice (n = 2). Proteins (75 μg/lane) were separated on 4–20% acrylamide/bis PAGE, transblotted, incubated with primary and secondary antibodies and visualized by fluorescence. C) Quantification of western blot 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 expression difference between db/db mice and C57BKS mice of the same gender (p≤0.05). Number signs (#) represent a statistically significant expression difference between male and female db/db mice or male and female C57BKS mice. Abcc3 expression was downregulated in db/db females and upregulated in db/db males as compared to respective controls. Abcc4 mRNA expression was upregulated in db/db males as compared to C57BKS males. Abcc1, 2, Abcg2 mRNA expression also remained unchanged in kidneys of these mice (data not shown).