Diurnal changes in the duration of mitosis in some tissues of young albino rats

Abstract

The duration of mitosis in the acinar cells of the pancreas varied from 1.7 to 2.5 h, in the hepatocytes from 1.3 to 5.2 h, and in the epidermis from 1.5 to 2.9 h. Diurnal changes in the mitotic index in the tissues investigated were due to both changes in the duration of mitosis and differences in the rate at which the cells commenced to divide. The renewal time of the tissues studied, although differing sharply in adult animals, was found to be about equal in rats aged 7 days (12.3 days in the pancreas and 20 days in the liver and epidermis).