Lung surfactant phospholipids as related to hydration and choline status of fasted rats.

Hydration status and choline nutrition were evaluated relative to the concentration of lung surfactant phosphatidylcholine (PC) in fasted rats. Rats deprived of food for 72 h showed lower voluntary water consumption and consistently lower levels of both PC and total phospholipid (TPL) present in isolated pulmonary surfactant than ad libitum-fed controls, although the ratio of surfactant PC to TPL and the residual PC and TPL concentrations were not different. Higher hematocrit values observed in the fasted animals were not altered by the administration of water or saline by orogastric tube nor was the low surfactant PC level corrected by fluid therapy. Evidence of choline deficiency was demonstrated in the fasted rats as there was a significant shift in hepatic PC:phosphatidylethanolamine; however, plasma choline levels did not change. The administration to fasted animals of up to 2.4 mmol of choline chloride via the drinking water (containing 60 mM choline) or an orogastric tube did not affect the plasma choline concentrations or the production of lung surfactant PC.