An organ culture system for study of fetal lung development

Fetal rat lungs placed in $\text{in}$$\text{vitro}$ organ culture at 15.5 days gestation grow significantly based on accumulation of DNA and protein. In the experimental system described, DNA accumulated rapidly during the first three days in culture and increased from 4.8 to 15.6 micrograms per lung culture. Protein content increased more slowly and reached a value more than double the initial value after six days in the culture system. Glycogen accumulated in the tissue during the first six days in culture and was depleted during the subsequent culture period, a pattern strikingly similar to that observed during lung development $\text{in}$$\text{vivo}$. Phospholipid accumulation was biphasic with respect to time with an inflection point at about the sixth day of culture. The phosphatidylcholine species synthesized in the culture system $\text{in}$$\text{vitro}$ were similar to those produced $\text{in}$$\text{vivo}$ in fetal lung at 21 days gestation.