EFFECT OF ADENOSINE ON GLUCOSE-METABOLISM OF RANA-RIDIBUNDA ERYTHROCYTES

The effects of adenosine and inosine on Rana ridibunda erythrocyte met abolism were studied. Adenosine can be metabolized by Rana ridibunda e rythrocytes as a carbon source for glycolysis to maintain ATP levels, whereas neither inosine nor glucose could maintain ATP levels. The rat e of lactate production was maximal (2.89 mumol ml-1 red cell h-1) in the presence of adenosine together with glucose compared with that in the presence of glucose or adenosine alone. Inosine sustained a simila r rate of lactate production as did glucose. The concentrations of pho sphorylated hexoses increased during 4h of incubation in the presence of adenosine either with or without glucose. The presence of sodium io doacetate accelerated the loss of ATP; furthermore, levels of lactate and pyruvate were significantly reduced in the presence of either aden osine or inosine. Ouabain strongly inhibited ATP and lactate formation in the presence of adenosine, whereas the levels of ATP and lactate w ere almost unchanged in the presence of inosine. An inhibitor of adeno sine transport, dipyridamole, impeded the increases in erythrocyte lac tate and ATP concentration in the presence of adenosine but did not mo dify the effects of inosine.