Rabbit corneal endothelial fluxes of sodium, bicarbonate, inulin, and dextran have been measured in ambient solutions containing either 0.5 mM adenosine alone (A), 0.3 mM glutathione alone (G), both adenosine and glutathione, or neither adenosine nor glutathione. Addition of A alone to a solution lacking both additives caused a decrease in both Jstrendo and Jendostr sodium fluxes coupled with an increase in Jstrendo net. Addition of G alone caused no effect, whereas addition of A and G together caused a decrease in both Jstrendo and Jendostr sodium fluxes and a large increase in Jstrendo net. Addition of A or G caused an increase in Jstrendo bicarbonate flux, but no change in Jendostr flux. Addition of A and G caused an increase in both Jstrendo and Jendostr bicarbonate flux and a decrease in Jstrendo net. None of the solution variations caused an alteration in either inulin or dextran permeability. Since both A and G influence Jstrendo net bicarbonate and sodium transport, this may provide an explanation of the beneficial effects of these compounds on the endothelium to both enhance and prolong corneal thickness and hydration regulation.