Figure 2.

Hypoxia- and low temperature–induced HIF-1α activation to promote transferrin expression both in vitro and in vivo. (A-C) After hypoxia treatment (1% O₂, 5% CO₂, and 94% N₂), HIF-1α and transferrin proteins in BNL CL.2 cells were analyzed by western blot analysis (A), and corresponding quantifications are shown in panels B and C. β-actin was used as loading control in panel A (n = 6). (D-F) Western blot detection of HIF-1α and transferrin levels in livers of normal and hypoxia-induced mice and corresponding quantifications (n = 6). (G-I) Western blot analysis of HIF-1α and transferrin levels in liver of normal and low temperature–induced mice and corresponding quantifications (n = 6). β-actin was used as loading control in panels D and G. (J-L) Transferrin levels in supernatant of HepG2 cells transfected by transferrin expression plasmid of wild-type hypoxia response elements (HRE; WT-HRE) or mutated HRE (MT-HRE) were analyzed by western blot analysis (J,K) and ELISA (L) after hypoxia treatment (n = 6). β-actin was used as loading control in panel J. Each experiment was independently repeated in triplicate. Data represent mean ± SD. Panels B, C, E, F, H, I, K, and L, ∗∗P < .01 by unpaired t test. Western blots were from different membranes, and representative blots are shown in panels A, D, G, and J. NC, normal control.