[Cell population kinetics and the cell population mechanism of circadian rhythm in the proliferative activity in the esophageal epithelium of mice maintained under constant illumination].

3H-thymidine was injected to male mice maintained either on a 12 hour light-dark cycle or on a prolonged continuous light (LL-group) at the peak of DNA synthetic activity of the esophagus epithelium (1a. m). The parameters of the diurnal rhythm of cell division and mitotic cycle of the basal layer were studied. In the LL-group of animals, an expressive asynchronization of diurnal rhythm of mitotic index was found. At the same time the labelled cell population revealed a slight degree of asynchronization. The data suggest that the process of asynchronization of the overall kinetics in the tissue throughout the whole day is associated with differences in the state of separate cell populations entering mitotic cycle at the various time of the day. The mitotic cycle duration in both groups of animals is almost alike and equal to 24-27 hours, i. e. is close to that of the diurnal rhythm.