Fig. 5. Effect of 20 µmol l^–1 L-histidine and 50 µmol l^–1 Cu⁺ on the time course of transmural transport of 20 µmol l^{–1 65}Zn²⁺. Values displayed are means ± S.E.M. of 3 replicates per time point. Slopes of the lines were calculated as regression lines using Sigma Plot software and the values on the figure (i.e. m-values) are the slopes obtained from these analyses at each condition used.