Hypoxia-inducible factor (HIF) plays an important role in regulating gene expression in response to ischemia. While activation of HIF-1 in muscle tissue was found during ischemia in vivo the meaning and mechanisms in isolated cells are still incompletely understood. Here we studied activation of HIF-1 in skeletal muscle cells cultured either in their undifferentiated myoblast state or differentiated into myotubes. HIF-1 was activated in myoblasts and myotubes by hypoxia and simulated ischemia. Induction of adrenomedullin mRNA and - to a lesser extent - VEGF mRNA well correlated with the induction of HIF-1 protein in both cell types. Enzymes of glycolysis like lactate dehydrogenase and pyruvate kinase showed upregulation of their mRNA only under hypoxic conditions but not during simulated ischemia. Phosphofructokinase mRNA showed no significant upregulation at all. Although HIF-1 was activated in myotubes during simulated ischemia myotubes died preceded by a loss of ATP. Myoblasts survived simulated ischemia with no decrease in ATP or ATP turnover. Furthermore, pharmacological inhibition of HIF-1 hydroxylases by dimethyl oxalyl glycine (DMOG) increased HIF-1 accumulation and significantly upregulated the expression of adrenomedullin, VEGF, lactate dehydrogenase and pyruvate kinase in myoblasts and myotubes. However, DMOG provided no protection from cell death. Our data indicate that HIF-1 - although activated in myotubes during simulated ischemia - cannot protect against the loss of ATP and cell viability. In contrast, myoblasts survive ischemia and may thus play an important role during regeneration and HIF-1-induced revascularization.