Studies of tissue permeability. VIII. The effect of anaerobiosis on glucose uptake in frog sartorius muscle.

Previous investigations of the effect of anaerobiosis on the metabolism of glucose have been carried out with mammalian tissues. Walaas and Walaas (1) found no difference in the rate of glucose uptake by rat hemidiaphragms incubated in Ringerphosphate solution with either oxygen or nitrogen as the gas phase. The addition of insulin exerted an effect on glucose uptake only during the first few minutes of anaerobic incubation. After 10 to 15 minutes of anaerobic incubation, phosphocreatine and adenosine triphosphate both fell to very low levels. Randle and Smith (2) reported that anaerobiosis did cause an increase in rate of glucose uptake if rat hemidiaphragms were incubated in bicarbonat’e rather than in phosphate buffer, at pH 7.4. In the perfused rat heart, which quickly stops contracting when deprived of oxygen, Morgan, Randle, and Regen (3) observed that anoxia increased the rate of penetration and phosphorylation of glucose. Frog muscle, in contrast to mammalian muscle, is known to retain its functional integrity after many hours of anaerobiosis (cf. Hill and Kupalov (4)). As part of t,his adaptation to anaerobic conditions, one finds that the adenosine triphosphate concentration remains unchanged even after 4 hours of anaerobic incubation at 29”. The characteristics of permeability of frog sartorius muscle to glucose in oxygenated bicarbonate-Ringer’s solution have been described (5) ; the muscle membrane has a very low permeability to glucose mlless insulin is added. In this paper it is shown that this is also the case under anaerobic conditions, at least during the first 2 hours of incubation. Thereaft,er, there is a pronounced increase in permeability to glucose. On addition of insulin, the rates of glucose penetration and phosphorylation in isolated frog muscle were found to be faster anaerobically than aerobically. The increase in rate of phosphorylation occurred despite a rise in the concentration of glucose 6.phosphate to levels which greatly exceeded the K; value of glucose B-phosphate that was determined for hexokinase in a frog muscle extract.