Studies of oxygen and volume restriction in cultured cardiac cells. II. The glucose effect.

An ischaemia-like state in cultured heart cells has been obtained by markedly restricting the volume of extracellular medium combined with total deprivation of oxygen (anoxia) and glucose. Cellular injury, as reflected by the release of both cytoplasmic and lysosomal enzymes was significantly greater than during anoxia alone (oxygen deprivation with a larger extracellular volume). This is most likely due to inadequate washout of metabolites during "ischaemia" rather than reduced energy production since glycolytic flux as reflected by lactate production was similar in both experimental states. Glucose administration during either anoxia or "ischaemia" delayed enzyme release. We believe that cytoplasmic enzymes are released mainly during the reversible period of oxygen deprivation, while lysosomal enzyme release reflects the onset or irreversible injury, occurring at a time when ATP levels and glycogen stores are almost completely exhausted.