Effects of SCN − and NO 3− on organic anion transport in rabbit kidney cortical slices

Abstract

1. 1. The effects of replacement of CI − by either SCN − or NO 3 − on the accumulation of p-aminohippurate, the efflux of pre-accumulated p-aminohippurate and kinetics of p-aminohippurate uptake were investigated in the rabbit kidney cortical slice. 2. 2. The total replacement of CI − in the incubation medium with SCN − decreased the 60-min slice-to-medium concentration ratio (S/M) of p-aminohippurate by 75% and that with NO 3 − by 40%. 3. 3. The decrease in p-aminohippurate accumulation by the inorganic ions was found to be specific for organic anion transport since the uptake of the organic cation, tetraethylammonium, was not influenced by inorganic ions. 4. 4. The influence of NO 3 − on p-aminohippurate uptake was fully reversible: however, the effect of SCN − could only be partially reversed. 5. 5. Both SCN − and NO 3 − significantly increased the K m value but had no significant effect on the V value of the p-aminohippurate uptake process. 6. 6. These findings suggest that both SCN − and NO 3 − are competitive inhibitors of p-aminohippurate transport and, also, that SCN − appears to bind to a membrane component involved in the transport of p-aminohippurate.