Hypoxia-inducible factor-1α (HIF-1α) transcriptionally regulates expression of several target genes in protecting tissues against hypoxia. With hypoxic stress, vascular endothelial growth factor (VEGF) is a signal protein produced by cells and further contributes to improvement of vascular functions and restoring the oxygen supply to tissues. In this current study, we first hypothesized that the protein levels of HIF-1α and VEGF are reduced in skeletal muscles of plateau animals [China Qinghai- Tibetan plateau pikas (ochotona curzoniae)] in response to hypoxia as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. We further hypothesized that HIF-1α plays a role in regulating expression of VEGF in skeletal muscle. Note that HIF-1α and VEGF were determined by using two-site immunoenzymatic assay (ELISA) methods. Our results demonstrated that hypoxic stress induced by exposure of lower O2 (6 h) significantly increased the levels of HIF-1α and VEGF in the oxidative and glycolytic muscles of SD rats and pikas (P<0.05 vs. normoxic conditions). Notably, the increases in HIF-1α and VEGF were significantly less in pikas (P<0.05, vs. SD controls) than in SD rats. In addition, a linear relationship was observed between amplified HIF-1α and VEGF in oxidative muscle (r=0.76 and P<0.01) and glycolytic muscle (r=0.72 and P<0.01) and inhibiting HIF-1α significantly decreased expression of VEGF induced by hypoxic stress in skeletal muscles (P<0.05). Overall, our findings suggest that (1) responsiveness of HIF-1α and VEGF in skeletal muscles to hypoxic stress is blunted in plateau animals, and (2) HIF-1α has a regulatory effect on VEGF under hypoxic environment., H.-C. Xie, J.-P. He, J.-F. Zhu, J.-G. Li., and Obsahuje bibliografii