가토 신피질 절편에서 PAH(ρ-aminohippuric acid) 이동에 미치는 음이온의 영향

Effects of Anions on PAH Transport in Rabbit Kidney Cortical Slices

The effects of anions on net accumulation of (ρ-aminohippuric acid)(PAH) were studied in rabbit kidney cortical slices. Experiments were carried while varying the major anionic composition of the incubation medium(replacement of Cl^- by isethionate and SCN^-). The total replacement of Cl^- with isethionate, SO₄^2- and SCN^- in the incubation medium decreased the 60-min slice-to-medium concentration(S/M) ratio of PAH to 60%, 40% and 50% of control value, respectively. The degree of inhibition in PAH accumulation by the replacement of isethionate and SCN^- was increased with increasing of both preincubation and incubation time. The influence of isethionate and SCN^- on PAH uptake was fully reversible. Both isethionate and SCN^- increased the apparent Km value significantly with no change on the apparent Vmax value, suggesting a competitive inhibition on PAH uptake. And the inhibitory effect of SCN^- on PAH uptake decreased with increase of pH in the incubation medium while that of isethionate increased with increase of pH. Intracellular water content, intracellular electrolyte concentration and oxygen consumption were not influenced by the replacement of Cl^- with isethionate or SCN^- in the incubation medium. These results suggest that both isethionate^- and SCN^- inhibit the PAH uptake by binding to some site necessary for normal PAH transport without affecting the cellular viability.