Extract: There is scant information regarding the contribution made by circulating precursors to pulmonary phosphatidylcholine synthesis in the developing mammalian lung. In situ pulmonary artery perfusions were performed in term New Zealand newborn rabbits with physiologic buffer containing either 3.6 mM or 10.8 mM glycerol. There was a twofold increase in nanomoles of glycerol-phosphatidylcholine synthesized at 30 min when the higher concentration of glycerol was used. Continuing with the higher concentration, a near three-fold increase was observed between the 30-min and 60-min perfusions. This data indicates that the de novo synthesis of pulmonary phosphatidylcholine is influenced by the concentration of glycerol in the perfusate as well as the duration of perfusion.Speculation: The observation that the concentration of circulating glycerol can influence the de novo synthesis of pulmonary phosphatidylcholine suggests that glycerol may also play a role in providing precursor for pulmonary surfactant synthesis. The biochemical similarity of lipid metabolism at birth between human newborn infants and the newborn rabbit encourages extrapolation of this data to humans. The question is raised as to the influence that intravenous glycerol at physiologic concentration would have on pulmonary phosphatidylcholine synthesis in the infant with hyaline membrane disease.
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