The MDR status of UWOV2 ovarian carcinoma cells was demonstrated, in part, by measuring the specific binding of [3H]AZD, a photoactive dihydropyridine calcium channel blocker known to bind to Pgp, and [14C]DXR to intact cells in culture at 4°C in the absence (control) or presence of 5 μg/ml TM (TM-treated) following an initial 16h pre-incubation at 37°C with or without the antibiotic. Here, PGP is linked to ovarian carcinoma.