Figure 1.

Parathyroid hormone increases the expression of Hif-1α both in vitro and in vivo. (a and b) Levels of Hif-1α, Hif-2α and Hif-1β protein were measured in wild-type osteoblasts at the indicated time points after treatment with 10 nmol·L⁻¹ PTH (a) and after 6 h of treatment with 200 nmol·L⁻¹ DFO (b). (c) Immunohistochemical analysis of Hif-1α expression in the trabecular bone of 10-week-old female wild-type mice treated with 40 μg·kg⁻¹ PTH or vehicle for 4 h. Representative tissue sections show increased Hif-1α expression in the osteoblasts (arrows) of PTH-treated mice relative to untreated controls. (d and e) mRNA levels of Hif-1α and Hif-2α were measured in vitro (d) and in vivo (e) after treatment with PTH or vehicle. Spp1 (Osteopontin) and Ptgs2 (Cox2) were used as controls. *P≤0.05. DFO, desferoxamine.