[Circadian changes in mitotic activity and DNA synthesis in hyperdiploid and hypotetraploid strains of Ehrlich's ascites tumor].

Noninbred male white mice received intraperitoneal injections of hyperdiploid or hypotetraploid strain of Ehrlich's ascites tumour. Fluctuations in the mitotic index were found both in the hypotetraploid strain at natural photoregime and in the hyperdiploid one with the period L:D-12:12 by the 4th, 5th and 6th days from the onset of tumour growth. The mitotic index reached the maximum values in the morning and in the day time. Circadian fluctuations of the mitotic and radioactive indices were not synchronous in different strains and under varying photoregimes. The data obtained point to significant differences in time organization of cell proliferation in Ehrlich's ascites tumour as compared to normal tissues.