Nucleic acids and protein content of some fetal and neonatal rat organs after insulin treatment.

In 17 1/2--21 1/2 day-old fetuses and 1--4 day-old rats the DNA, RNA and protein content of the liver, heart and brain was daily investigated 6 hours after injecting approximately 40 mU . g-1 insulin. The DNA content in the mentioned organs was not affected by the insulin. The RNA content in the fetal and neonatal brain and neonatal heart was significantly elevated, while the liver RNA was not altered. Only in the 4 day-old brain did the protein content increase. The experimental dates indicate that the cell RNA content of some perinatal tissues can be elevated by insulin depending on the type of tissue and its developmental stage.