FIGURE 4. Effect of ¹³¹I irradiation (D_c = 80 Gy) and equimolar concentrations of stable iodide (10^-8 mol/L) on subsequent (3 d later) basal-to-apical ¹²⁵I transport. Results are given as ¹²⁵I activity transported into apical medium at indicated times relative to activity added to basal medium at time = 0. Values obtained are expressed as percentage of total activity present basally at start of experiment. Results are expressed as mean ± SEM (n = 3).