Studies on the control of the mitotic activity in white mice. II. Diurnal variations in the mitotic activity of epidermis and intestinal glands and in the level of liver glycogen
Dziekanowska, Danuta; Nowak, A.
Acta Physiol Polon 13(6): 700-705
The authors have shown that in white mice a roughly inverse relationship exists between the blood sugar and the mitotic activity of the epidermis and cornea. The aim of the present study was to determine the degree of relationship between the mitotic activity of various tissues and the diurnal variation of the glycogen level. Studies were made: on the skin small intestine, and on a part of the left lobe of the liver. Each tissue was fixed, embedded, cut into slices and stained with hemato-xylin-eosine or by the PAS method of Hotchkiss. The number of mitoses was counted. The level of glycogen was determined by direct counting of the percentage of cells which contained glycogen in the individual lobule according to Holmgren. The authors observed diurnal variations in the mitotic activity of epidermis and mucous glands of the intestine. Peak activity occurred at 6 a.m. whereas the least active mitosis was observed in the evening. The mitotic activity of the various tissues studied (epithelium of the cornea, epidermis and glands of the intestinal mucosa) exhibits a similar pattern independent of the absolute frequency of mitosis in the particular tissue. The variation of the liver level of glycogen is roughly inverse to that of the blood sugar. The diurnal variation of the liver glycogen level is roughly parallel to the variation of the mitotic activity of the tissues studied. However, the highest and lowest levels of glycogen precede the highest and lowest frequencies of mitosis, respectively. It may be assumed that carbo-hydrates provide the energy cell division.