[Effect of an erythrocytic chalone on the postsynthetic period of the erythroblastic mitotic cell cycle in mouse bone marrow].

The effect of the erythrocytic chalone on the beginning, middle and end of the G2-period of the mitotic cycle has been studied in the erythroblastic cells of the mouse bone marrow. The end of S(-) and the beginning of G2(-) periods have been demonstrated to be the most sensitive to the effect in question. The erythrocytic chalone inhibits mitotic activity by decreasing the amount of prophases and inhibits incorporation of radioactive glycine into the dividing erythroblastic cells. The mechanism inhibiting their mitotic activity is discussed.