Demonstration of active sodium transport across the isolated rabbit corneal endothelium

The recent demonstration of sodium-sensitivity and chloride-insensitivity of the bicarbonate transport system of the rabbit corneal endothelium promoted a further examination of sodium fluxes across this membrane. Unidirectional fluxes were measured on paired endothelia at steady state. A net sodium flux from stroma to aqueous was found with a value of 3.5 muequiv/cm2/hr (almost double that of bicarbonate transport), which was independent of the ambient bicarbonate concentration.