Figure 4

Concentration Dependences of Uptake by Mice Kidney Slices. (A) Uptake of [³H]Ergothioneine (1, 5, 10, 50, 100 and 250 μM) into mice kidney slices was measured at pH 7.4 and 37 °C for 3 min. The data were fitted to the Michaelis-Menten equation and Eadie-Hofstee plot by a nonlinear least-squares regression analysis. Each point represents the mean ± S.E.M. (n = 3 or 4), after subtraction of the uptake of [³H]Ergothioneine (1,000 μM). (B) Uptake of [³H]Gly-Sar (10, 30, 50, 100, 300 μM) into mice kidney slices was measured at pH 7.4 and 37 °C for 5 min. The data were fitted to the Michaelis-Menten equation and Eadie-Hofstee plot by a nonlinear least-squares regression analysis. Each point represents the mean ± S.E.M. (n = 3 or 4), after subtraction of the uptake of [³H]Gly-Sar (10 mM). (C) Uptake of [³H]ergothioneine (1.0 μM) into mice kidney slices was performed at pH 7.4 and 37 °C for 3 min in the absence or presence of verapamil (10, 30, 100, 300 and 1,000 μM). Each point represents the mean ± S.E.M. (n = 3), after subtraction of the uptake of [³H]ergothioneine in the absence of Na⁺. (D) Uptake of [³H]carnitine (1.0 μM) into mice kidney slices was performed at pH 7.4 and 37 °C for 3 min in the absence or the presence of verapamil (10, 30, 100, 300 and 1,000 μM). Each point represents the mean ± S.E.M. (n = 3), after subtraction of the uptake of [³H]carnitine in the absence of Na⁺. (E) Uptake of [¹⁴C]αMG (1.0 μM) into mice kidney slices was performed at pH 7.4 and 37 °C for 3 min in the absence or presence of phloridzin (10, 30, 100, 300, 1,000, 3,000 and 10,000 nM). Each point represents the mean ± S.E.M. (n = 3), after subtraction of the uptake of [¹⁴C]αMG in the absence of Na⁺.