Figure 3.

Characterization of hOAT1 expressed in OK cells. (A) Sis-inhibitory effect of various compounds on PAH uptake. The hOAT1-transformed cells were incubated with 200 μl of Dulbecco's PBS containing 5 mM D-glucose, 10 μM D-[³H]-mannitol, 10 μM of [¹⁴C]-PAH and indicated concentrations of competitors for 10 min at room temperature. Extracellular trapping and nonspecific uptake were obtained from the radioactivity of nontransportable D-[³H]-mannitol. Values are mean±s.d. (n=4). Abbreviations are α-ketoglutaric acid (αKG) and tetraethylammmonium (TEA). (B) Trans-stimulatory effect of α-ketoglutaric acid on expressed hOAT1. The hOAT1-transformed cells were pretreated with 1 mM of α-ketoglutaric acid for 2 h and PAH uptake assay was performed. Values are mean±s.d. (n=4).