Characterization of organic anion transporter in cultured rat C6 glioma cells

초록

In human body, the excretion of organic anions, including numerous endogenous and exogenous compounds is mainly performed by transport protein in the liver and kidney. These organic anions (such as a number of clinically used drugs, pesticides and herbicides) are chemically heterogeneous substances that possess a carbon backbone and a net negative charge at physiological pH. Several integral membrane protein families serve as organic anion transporters. There are ATP binding cassette, organic anion transporting protein and organic anion transporter (OAT). Among these OATs (including OAT1, 2 and 3) have extremely wide spectrum of substrate specificity. They mainly expressed in the brain, liver and kidney. The purpose of this study is to clarify the expression and characterization of OATs in cultured rat C6 glioma cells. The expression of OAT1, 2 and 3 was determined using reverse transcription-polymerase chain reaction (PCR) and Western blotting analysis. Among these three isoforms of OATs, OAT3 messenger RNA was detected in cultured rat C6 glioma cells. No RT-PCR products of OAT1 and 2 were observed. By Western blot analysis, OAT3 protein was detected in plasma membrane fraction of cultured rat C6 glioma cells. The isotope labeled para-aminohippuric acid, estrone sulfate and dehydroepiandrosterone sulfate uptake at 37 degree were significantly increased comparing those of control (at 0-4 degree). The uptake was inhibited by some organic anion chemical/drug and several sulfate conjugates. From these results, obtained data would contribute to understanding of therapeutics and patho-physiology of glial cells.