The effect of colchicine and 3H-thymidine on the proliferation and mitotic cycle of cells of different rudiments of the chick embryo has been studied during gastrulation. Colchicine (1-10-6 g/ml) was shown not to influence both the portion of cells synthesizing DNA and entering mitosis and the intensity of DNA synthesis. No changes in the intensity of cell entrance in mitosis and the frequency of mitotic figures were found following the injection of 3H-thymidine (4.1 Cu/mM) at a dose of 2.5 muCu per egg. Taking into account the great possibilities of the complex utilization of stathmokinetic and autoradiographic methods for studying the kinetics of developing cell populations, a conclusion is drawn that the chick embryo at the early developmental stages is a convenient model for such an analysis.
Animals Cell Cycle