INVIVO DEMONSTRATION OF THE BICARBONATE ION-PUMP OF RABBIT CORNEAL ENDOTHELIUM

The bicarbonate concentration in the stromal fluid of rabbit corneas in vivo is depressed by more than 50% of its level in the aqueous humour. After allowing for ion-exchange effects, electrochemical potential effects, binding phenomena, compartmentalization and pH effects, apparently most of the depression is caused by an active efflux of bicarbonate ions out of the stroma. Simple flux analysis suggests that the magnitude of the active bicarbonate efflux equals that previously measured to pass across the endothelium in the in vitro preparation.