The efflux of rubidium from the rabbit lens

Rabbit lenses which had accumulated Rb were incubated in a medium containing sufficient nonlabeled rubidium (33 mM.) to saturate the carrier or concentrations of ouabain (10-*M) which inhibited the transport system. The rate of runout of Rb so determined could be increased by reducing the concentration of calcium in the medium or by the addition of such metabolic inhibitors as iodoacetate, fluoride, and cyanide. Several corticosteroids which did not alter Rb uptake did increase its efflux. Decapsulation of the lens with collagenase failed to alter Rb uptake or runout.