Effects of hypoxia on norepinephrine uptake by developing rabbit lung.

Pulmonary extraction of radiolabeled norepinephrine (NE) was evaluated in newborn rabbits aged 1 to 3 days. Twenty pups were raised from birth in an hypoxic environment (FiO2 = 0.16-0.17) and 10 were raised in room air for study as controls. NE extraction was measured using an isolated, perfused lung technique. In hypoxic animals, average percent removal of NE was significantly reduced (p less than 0.05) as compared to controls while pulmonary pressures were increased (p less than 0.05) compared to controls. The data suggest that hypoxia reduces the ability of the lung to clear norepinephrine. This may be a factor in systemic and pulmonary vasomotor responses to hypoxia.