Fig. 4. Inhibition of FL accumulation by glutathione and a size range of its conjugates. All inhibitor concentrations are 0.2 mmol l^–1; sample sizes are 6 tubules, except for `no inhibitor, which represents all control trials (N=23). ^*Change in uptake rate (second measurement period relative to first measurement period) in presence of inhibitor significantly different from uptake rate in absence of inhibitor; P<0.05, paired t-test.