198 EFFECTS OF INSULIN AND THEOPHYLLINE ON GLYCOGEN CONTENT OF FETAL RAT LUNG IN ORGAN CULTURE

Abstract

Control of maturation of the fetal lung is poorly understood. Since fetal lung maturation is characterized by both accumulation of phosphatidylcholine (PC) and loss of glycogen in aveolar type II cells, control of these events may be effected by similar agents. Previous studies have indicated that insulin delays morphologic maturation and that theophylline stimulates PC synthesis in fetal rat lung in organ culture.We have investigated the effects of insulin and theophylline on the glycogen content of 19 day fetal rat lung in organ culture. In explants cultured without added hormones, glycogen content decreased by 34% after 24 hrs in culture and 70% after 48 hrs. During this time there was morphologic and biochemical evidence of lung maturation. Treatment of the explants with insulin (0.1u/ml) for 24 hrs resulted in a 34% increase in the glycogen content compared to controls. Theophylline treatment (1.0mM) of the explants resulted in a 53% decrease in glycogen after 48 hrs. The glycogen content of fetal lung explants is affected by agents known to influence pulmonary maturation and PC synthesis. Supported by USPHS grant no HL19752.