| Abstract: | The biphasic circadian rhythm of mitotic activity has been demonstrated in a 5-day Ehrlich's ascites carcinoma (EAC) in mice. Adrenaline injected intraperitoneally in a dose of 1.5 micrograms/g bw produced an inhibitory effect on cell division that lasted over 4 hours and reached maximum at injection to mice during light time of the day. EAC extract in a dose of 1 ml also inhibited the mitosis during 4 hours, but the greatest fall in the mitotic activity was observed during the minimum mitotic activity in the control animals. Combined administration of adrenaline and the extract resulted in the phenomenon of prolonged inhibition of cell division, that persisted for maximum 6-8 hours, if the preparations were injected in the middle of the day light time. Of definite importance was the rhythm of changes in the sensitivity of proliferating tumor cells. |
