@article {Mandery345, author = {Kathrin Mandery and Krystyna Bujok and Ingrid Schmidt and Thomas Wex and Gerhard Treiber and Peter Malfertheiner and Tilman T. Rau and Kerstin U. Amann and Kay Brune and Martin F. Fromm and Hartmut Glaeser}, title = {Influence of Cyclooxygenase Inhibitors on the Function of the Prostaglandin Transporter Organic Anion-Transporting Polypeptide 2A1 Expressed in Human Gastroduodenal Mucosa}, volume = {332}, number = {2}, pages = {345--351}, year = {2010}, doi = {10.1124/jpet.109.154518}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {The human organic anion-transporting polypeptide 2A1 (OATP2A1) is a prostaglandin transporter expressed in several tissues and plays an important role for local distribution of prostaglandins, which contribute to the integrity of gastric mucosa. Blockade of prostaglandin pathways by cyclooxygenase (COX) inhibitors has been associated with serious side effects such as gastrointestinal ulceration and bleeding. However, little is known regarding OATP2A1 expression in the upper gastrointestinal tract and the potential impact of cyclooxygenase inhibitors on OATP2A1 function. We first investigated the expression of OATP2A1 mRNA and protein in human gastroduodenal mucosa using human biopsy specimens obtained from antrum, corpus, and duodenum. The results indicate that OATP2A1 is expressed in the neck region and deep pyloric glands of antrum and in parietal cells of gastric corpus. Second, we examined various COX inhibitors for their effects on OATP2A1 transporter activity. Using HEK293 cells expressing OATP2A1, we found that diclofenac and lumiracoxib are potent inhibitors of OATP2A1-mediated transport of prostaglandin (PG) E2 with IC50 values of 6.2 {\textpm} 1.2 and 3.1 {\textpm} 1.2 μM. In contrast, indomethacin, ketoprofen, and naproxen led to significant stimulation of OATP2A1-mediated PGE2 transport by 162.7 {\textpm} 13.9, 77.2 {\textpm} 3.6, and 32.3 {\textpm} 4.9\%, respectively. Taken together, our results suggest that various clinically used COX inhibitors have differential impact on the function of the prostaglandin transporter OATP2A1 in human stomach and that these effects may contribute to differences in the gastrointestinal side effects of COX inhibitors. Copyright {\textcopyright} 2010 by The American Society for Pharmacology and Experimental Therapeutics}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/332/2/345}, eprint = {https://jpet.aspetjournals.org/content/332/2/345.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }