[Dynamics of incorporation of 3H-actinomycin D into synchronized Chinese hamster cells].

Dynamics of 3H-actinomycin D (3H-AMD) incorporation has been studied in the Chinese hamster synchronized cell culture (line 237) during different cell cycle phases. Intensive isotope inclusions were seen in cells during interphase: in the beginning of G1 period, in the early S period, and in the late S period, during the cell passage to G2 stage. The authors suggest that the binding of 3H-AMD by cells may be due not only to conformational changes of DNA structure, but also due to the variation in cell membrane penetration throughout the mitotic cycle.