Abstract
Alveolarization in the rat occurs during the first 21 days and provides surface area proportional to oxygen needs. Lung size is known to increase in distance runners and persons living at altitude. Rat dams with 7–1 day old pups (HR), were placed 0.12 Ox in a recirculating chamber using Nx to reduce O2 and soda lime to absorb CO2. Control dams and comparable litters of pups (CR) were raised in 0.21 O2 under similar conditions. At 20–21 days HR and CR pups were weighed, injected with [14C] methylcholine, and the lungs removed, weighed, and homogenized. A lamellar body (LB) fraction was derived by sucrose density centrifugation and LB disaturated phosphatidylcholine (LBPC) was extracted, quantitated, and the specific activity determined. HR pups were hyperpneic and runted significantly as compared to CR (36.1g vs 51.4g, p<0.001), although HR and CR lung weights were not different (1.41g vs 1.38g) and the % dry weights were comparable (HR 21.0 vs CR 20.6). LW/BW however, was significantly increased in HR (0.039 vs 0.028 p<.005). LBPC/g lung was comparable in HR and CR (209.1 vs 194.2). The accumulations of label in LBPC (dpm/μmol /min) as an index of synthesis was higher in HR (183.7 vs 291.9, p<.001). These data show decreased body growth but not lung growth in response to hypoxia. The increase in LBPC labelling suggest more rapid synthesis of surfactant lipid perhaps in response to hyperpnea.
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Buohter, D., Franke, K., Brown, L. et al. 244 HYPOXIA, LUNG GROWTH AMD THE SURFACTANT SYSTEM DURING ALVEOLARIZATION. Pediatr Res 19, 151 (1985). https://doi.org/10.1203/00006450-198504000-00274
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DOI: https://doi.org/10.1203/00006450-198504000-00274
