Functional analysis and androgen-regulated expression of mouse organic anion transporting polypeptide 1 (Oatp1) in the kidney

Abstract Mouse Oatp1 was recently identified as a new murine member of the organic anion transporting polypeptide (Oatp) family and suggested to represent the counterpart of rat Oatp1. Northern blot analysis detected expression of several mouse Oatp-transcripts predominantly in liver and kidney. In the present study we describe the strict androgen-dependent expression of mouse Oatp1 mRNA in kidney and obtained further information about its substrate specificity using Xenopus oocytes. In addition to the previously reported estrone-3-sulfate, we demonstrate that mouse Oatp1 mediates sodium-independent uptake of the anionic steroid conjugates dehydroepiandrosterone sulfate ( K m ∼8 μM) and estradiol-17-glucuronide ( K m ∼5 μM) and also of the prostaglandin PGE 2 .