... comparison of rhodamine uptake, in the presence and the absence of uncouplers, allows the estimation of the effect of intracellular binding on the MDR phenomenon. The data detailed obtained in the present ... quenching of the dyes; and (c) it measures the total dye amount associatedwith the cells, including the dye adsorbed to the sur-face of the cells.To avoid complication of the uptake studies by active ... with the accumulation of dyes, and probably certain drugs,in the cytoplasm. On the other hand, high-affinitybinding of these agents to intracellular receptors over-whelms the low levels of ABC...