Meeting Abstract
P1.212 Friday, Jan. 4 The Organic Anion Transporting Protein (OATP) Family in a Teleost Fish Model MUZZIO, A.M.*; NOYES, P.D.; STAPLETON, H.M.; LEMA, S.C.; CalPoly, San Luis Obispo; Duke University; Duke University; CalPoly, San Luis Obispo slema@calpoly.edu
Organic anion transporting proteins (OATPs) are a family of transmembrane polypeptides that regulate the sodium-independent cellular transport of amphipathic organic compounds including xenobiotics, hormones and pharmaceuticals. Recent studies in mammals have demonstrated a role for OATPs in the endocrine disrupting effects of environmental pollutants, yet many basic questions remain unaddressed about the evolutionary diversity, function and regulation of OATPs in other vertebrate taxa. Here, we identified and confirmed ESTs encoding eight distinct OATPs in a teleost fish model, the fathead minnow (Pimephales promelas). We then used quantitative real-time RT-PCR methods to examine the relative abundance of OATP mRNAs in the brain, liver, gonads, spleen, heart, skeletal muscle, kidney, gills, and GI tract of adult fish. Gene transcripts encoding OATP2a1 and 5a1 transporters were ubiquitous in all minnow tissues examined, with 2a1 mRNAs most abundant in the liver and 5a1 transcripts at highest levels in the brain, gonad and heart. Transcripts for OATP1c1 were most abundant in the liver but also found at elevated levels in the brain, while OATP3a1 mRNAs were greatest in heart and muscle and OATP2b1 mRNAs highest in heart and gills. Transcripts for OATP4a1 were detected at greatest abundance in the brain, with high levels in optic tectum, moderate levels in hindbrain and forebrain, and lower levels in the cerebellum. OATP4a1 mRNAs were also abundant in the ovary but not in the testes. Transcripts for OATPs 1f4 and 1f2 were highly abundant in the kidney but nearly absent in other tissues. Taken as a whole, our findings help establish the tissue distribution of the OATP family and provide a foundation for exploring the regulation of OATP transcriptional dynamics by hormones and xenobiotics.
