Rabbit lenses incubated in vitro in potassium-free Tyrode's solution for 4 hours accinnulated trace amounts of Rb-86 to a concentration averaging 18 times that of the incubation medium. The uptake of Rb-86 was temperature dependent and required calcium. In the presence of glucose it was inhibited by iodoacetate, ouabain, or digoxin, but not by dinitrophenol, fluoroacetate, or anaerobiosis. The ...