Diurnal variations in mitotic activity in mice

Summary A study was made of the regularities in the 20-hour changes in the mitotic activity of intestinal epithelium of the salivary glands, pancreas, kidney, epidermis and corneal epithelium of mice. Changes of the functional activity of these organs were recorded simultaneously. Regular 24-hour changes of mitotic activity were noted in various test organs. The 24-hour mitotic rhythm curves had two peaks in the case of digestive organs: in case of the kidney the curves were also double-peaked, the peaks, however, being less marked. The second peak of the cellular mitotic activity curve is connected with the regimen of the animal feeding. The curves of the 24-hour rhythm of the number of mitoses had a single peak in the case of corenal epithelium and epidermis. In the 24-hour changes of the cellular mitotic activity there existed a reverse relationship between the number of dividing cells and the functional activity of the organ.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 53, No. 4, pp. 100–104, April, 1962