Effect of semicarbazide on the perinatal development of the rat: changes in DNA, RNA and protein content

Semicarbazide was injected intraperitoneally to pregnant rats in single doses of 50, 75, 100 or 150 mg/kg. Treatment was administered on days 7, 10 or 13 of pregnancy. Semicarbazide produced abnormalities in 21 day old fetuses, found mainly in liver and kidney and in the skull and sternum, as well as resorptions and fetal deaths throughout gestation. This substance also caused a high postnatal mortality rate during the first month of life, especially with the 100 mg/kg dose. This dose reduced the nucleic acid and protein content in the lung and liver of the rats whether they were adult, pregnant, fetus or newborn. Statistically significant decrease of the nucleic acid level in adult rats appeared 48 hours after treatment. This decrease varied in the two organs studied. The lungs of pregnant rats which received semi-carbazide on day 10 of gestation showed a statistically significant decrease of the nucleic acid and protein levels on day 18 of gestation; there was also a significant decrease of RNA in the liver on this day, while a decrease in the proteins did not appear until day 21. The fetuses of treated mothers showed a significant decrease of DNA and RNA in the lung when they were 21 days old and a continuous decrease of the protein levels lasting up to the end of the first week of life. DNA and RNA in the liver of these offspring decreased when they were 30 days old. As for the protein content, it decreased throughout fetal life and continued to do so during the first month of fetal life.