A cDNA coding for 551 amino acids was identified by sequence analysis as novel human organic anion transporter and called hOAT7. RT-PCR analysis of the tissue distribution in twenty different human tissues showed an ubiquitous expression of one splice variant of hOAT7 including intestine and colon, whereas a second splice variant was almost exclusively and strongly expressed in the kidneys. A functional proof of hOAT7- mediated organic anion transport was carried out in Xenopus laevis oocytes resulting in a substantial transport of [³H]p-aminohippurate as well as [¹⁴C]urate. hOAT7 is speculated to be expressed at the apical side of proximal tubule cells. Consequently, we examined its driving forces in comparison to the urate transporter hURAT1. hOAT7-mediated [¹⁴C]urate uptake was significantly inhibited by L-lactate, pyrazinoate and nicotinate, but only pyrazinoate trans-stimulated [¹⁴C]urate uptake to a significant extent, indicating an exchange mode of action for hOAT7. This idea is further supported by hOAT7- mediated [³H]nicotinate uptakes, which was trans-stimulated by nicotinate and low pH-values of the external medium suggesting an nicotinate/nicotinate or nicotinate/OH^-exchange. Showing a K_m value of 44 mM for nicotinate, we conclude that hOAT7 is the first molecularly identified high affinity nicotinate transporter in intestine and kidneys.