GROWTH AND MITOTIC ACTIVITY OF LUNG COLONIES DERIVED FROM MOUSE TERATOCARCINOMAS

This study dealt with the mitotic activity of lung colonies in the process of differentiation of mouse teratocarcinoma cells injected in vivo. The results showed that three stages were identifiable in respect to the mitotic activity: 1) a lag stage for a few days after injection, 2) a stage during which maximum mitotic activity is observed for several days following the first stage and 3) a third stage displaying a decrease in mitotic activity. There is a correspondence between these three steps in mitotic activity and differentiation in lung colonies previously identified by histological observations.