FIGURE 2.
Effects of lung-specific deletion of HIF1α. A, graph of the percent viability of pups at birth versus intrauterine doxycycline treatment days. Doxycycline-induced lethality was more pronounced when the drug was delivered more than 4 days before parturition (circles). No lethality was observed in the control group (no doxycycline, squares) or other possible genotype controls (data not shown). B, at birth HIF1αΔ/Δ pups (14 day in utero exposure) were cyanotic (right) compared with normal, pink well oxygenated controls (left). C, mean lung weights of control (black bar) and HIF1αΔ/Δ pups (white bar, exposed to doxycycline for more than 8 days). The asterisk indicates a significant difference, p value < 0.01. D, vial containing excised lungs from newborn pups. Lungs from HIF1αΔ/Δ (Δ/Δ, 14 day doxycycline exposure) pups sink whereas control (Ctrl) lungs float in saline.