Hypoxia in fibroblast cultures. I. Changes in glucose consumption by 5 vol.-% oxygen concentration and reduced pH.
In secondary cultures of rat embryonic fibroblasts the glucose consumption and lactate concentration were comparatively investigated in 5 and 21 Vol.-% O2 environment at pH 6.6 and pH 7.4 (HEPES-buffer). The results were correlated with cell density. The following observations were made: 1. At pH 6.6 the rate of cell proliferation was reduced to 81%; by additional hypoxia it was reduced to 71%. 2. Increase in cell density effectuated decrease of glucose consumption and lactate production at pH 7.4 and pH 6.6 in 5% as well as in 21% O2 environment. 3. At pH 7.4 enhancement of glucose consumption and lactate production due to hypoxia can be observed only at low cell density. 4. At pH 6.6 respiration of fibroblasts was little influenced by 5% O2 environment. 5. Transition from pH 7.4/21% O2 to pH 6.6/5% O2 effectuated decrease in glucose consumption and lactate concentration in tissues in hypoxic environment. This suggests a pH-governed feedback mechanism. Abbreviations used in the text: c-AMP = cyclic adenosine monophosphate; MPS = acid mucopolysaccharides (glycosaminoglycans).
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D002645:Chickens; D005347:Fibroblasts / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats
D005947:Glucose