... transport in the presence but not in the absence of GSH [12,45,46]. Thus the effect of vincristineon the cGMP uptake was also tested in the presence of Table 2. Fitting parameters for uptake of [3H]DNP-SG ... Iniþ Unoninh; 1 ¼ ni¼ 2 ð3Þwhere I is the concentration of the inhibitor, IC50is theinhibitor concentration producing 50% inhibition of theinhibitable component, U0is the uptake in the ... clotrimazole, creatine kinase, creatinephosphokinase, daunorubicin, dideoxyforskolin, iso-butylmethylxanthine (IBMX), doxorubicin, estradiol 17-b-D-glucuronide, forskolin, glibenclamide, glutathione(reduced...