➦ The human sodium dependent organic anion transporter (SOAT) shows highly specific transport activity for sulfated steroids. SOAT substrates identified so far include dehydroepiandrosterone sulfate, 16α-hydroxydehydroepiandrosterone sulfate, estrone-3-sulfate, pregnenolone sulfate, 17β-estradiol-3-sulfate, and androstenediol sulfate. In humans SOAT is predominantly expressed in the testis with lower expression in the placenta and breast tissue. In the testis, SOAT was localised to spermatocytes and round spermatids and, therefore, this carrier is supposed to play a role in testicular steroid regulation and male fertility.