Metabolic requirements for anaerobic active Cl and Na transport in the bullfrog cornea

In the bullfrog cornea, the relationships between the rates of aerobic and anaerobic glycolysis and active Cl and Na transport were studied. In NaCl Ringer (glucose-free), the short-circuit current (SCC) declined much more slowly under aerobic than under anaerobic conditions. The aerobic lactate effluxes in glucose-free and glucose-rich NaCl Ringer were 0.08 and 0.23 μmol/h.cm², respectively. The transition to anoxia caused these values to increase significantly and was accompanied by depletion of endogenous glycogen in glucose-free Ringer. In Na₂SO₄ Ringer, amphotericin B (10^-5 M) stimulation of the aerobic SCC was not dependent on the presence of glucose but under anoxia, SCC stimulation required glucose. In Na₂SO₄ (glucose-rich) Ringer, amphotericin B stimulated the aerobic lactate efflux from 0.26 to 0.36 μmol/h.cm² and anoxia increased it to 0.55 μmol/h.mol². In NaCl Ringer, the addition of either 0.5 mM adenosine or 1 mM ATP with 26 mM glucose restored the anaerobic-inhibited SCC and lactate efflux of glucose-depleted corneas. The results show that the reactions of glycolysis are a sufficient energy source for supporting active Na and Cl transport.