Lung lipid metabolism after 7 days of hydrocortisone administration to adult rats.

Pathogen-free rats were given either hydrocortisone (4 mg) or saline by intraperitoneal injection twice daily for 7 consecutive days. Lung weight, body weight, DNA, and total phosphatidylcholine content in lungs were equal in the saline and hydrocortisone groups. Lungs of rats receiving hydrocortisone had 23% more saturated phosphatidylcholine (P less than 0.001) and 7% less unsaturated phosphatidylcholine (P greater than 0.05). When tissue slices of these lungs were incubated with radioactive glycerol and palmitate, the incorporation of radioactivity into saturated phosphatidylcholine from animals given hydrocortisone was significantly higher (P less than 0.001 and P less than 0.05, respectively). Incorporation of radioactivity from lysophosphatidylcholine into phosphatidylcholine was 10 times greater than from glycerol or palmitate, but hydrocortisone had no effect. These results suggest that lysophosphatidylcholine may be an important precursor for phosphatidylcholine synthesis, especially saturated phosphatidylcholine, and hydrocortisone may lead to increased de novo synthesis of phosphatidylcholine.