Translacental effect of urethane on DNA synthesis in mouse embryonic lung tissue in organotypical culture

Abstract

The dynamics of DNA synthesis in organ cultures of line A embryonic mouse lung tissue (intact and exposed to the transplacental action of urethane) was studied by an autoradiographic method. Under the transplacental influence of urethane inhibition of DNA synthesis took place in the embryonic lungs on the first day. The labeling index fell by about two-thirds. It recovered during the next two days, and subsequently was higher than normally. The maximal labeling index in the experimental explants occurred on the 7th day of culture, i. e., on the 8th–10th day after transplacental action of urethane on the lung tissuein utero. The labeling index fell toward the 15th day of culture, but was still higher than in the intact explants; by the 21st day in intact cultures DNA synthesis had ceased completely, whereas it still continued in the experimental cultures.