ON THE DIURNAL CYCLE OF MITOTIC ACTIVITY IN THE CORNEAL EPITHELIUM OF MICE

1958 ◽  
Vol 33 (3) ◽  
pp. 230-237 ◽  
Author(s):  
Raimo Vasama ◽  
Ritva Vasama
Keyword(s):  
Mitotic Activity ◽  
Diurnal Cycle ◽  
Corneal Epithelium

Age and Mitotic Activity in the Male Mouse, Mus Musculus L

1949 ◽  
Vol 26 (3) ◽  
pp. 261-286
Author(s):  
W. S. BULLOUGH
Keyword(s):  
Mitotic Activity ◽  
Diurnal Cycle ◽  
Male Mouse ◽  
Middle Age ◽  
Sugar Content ◽  
Rest Period ◽  
Point Of View ◽  
Bodily Activity ◽  
Vital Factor ◽  
Mitosis Rate

1. A study has been made of the mitosis rate and of the diurnal cycles of male mice during each of the first 20 months of life. The mice used belonged to the Kreyberg's white label and the Strong's CBA strains. Most of the observations were made on the ear epidermis, but some attention was also given to other tissues. 2. It was discovered that, when judged from the point of view of mitotic activity, the life of a male mouse consists of four ages. During the immature age the animals are still growing and their mitosis rate is generally high, although the ear epidermis provides an exception to this rule. During the mature age which lasts from about the 3rd to the 12th month the mitosis rate is lowered. During the middle age which follows the mitosis rate increases, but in senility it is again reduced. 3. Coincident with these changes in the mitosis rate are changes in the spontaneous bodily activity. The mice are most active during immaturity and maturity. In middle age their activity is reduced by about half, and in senility they spend almost the whole time resting. Particularly in the Strong's CBA mice there are also changes in the timing of the diurnal cycle of spontaneous bodily activity, and these are immediately mirrored by changes in the timing of the diurnal cycle of mitotic activity so that throughout life a general inverse relationship between bodily activity and mitotic activity is maintained. 4. In middle-aged Strong's CBA males the daily rest period extends almost without interruption from 06.00 to 18.00 hr. However, the most active cell division develops only at the beginning of this period, and it is evident that in prolonged sleep a lack of some vital factor develops. It is shown that subcutaneous injections of starch overcome this lack in sleeping mice and result almost immediately in the redevelopment of a high mitosis rate. Thus it would appear that sugar is the vital factor involved, and that the sugar content of the tissues is quickly used up during high mitotic activity. 5. These results are discussed particularly in relation to the problem of carcinogenesis.

A Diurnal Cycle in the Mitotic Activity of Ascites Tumour Cells in Mice

Nature ◽  
1957 ◽  
Vol 180 (4588) ◽  
pp. 705-706 ◽  
Author(s):  
I. P. S. AGRELL ◽  
ELSA WELIN-BERGER
Keyword(s):  
Mitotic Activity ◽  
Diurnal Cycle ◽  
Tumour Cells ◽  
Ascites Tumour ◽  
Ascites Tumour Cells

scholarly journals The Relationship of Carbohydrate Metabolism and Mitotic Activity in the Mouse

1952 ◽  
Vol 29 (2) ◽  
pp. 328-335
Author(s):  
JOHN O. LAWS
Keyword(s):  
Mitotic Activity ◽  
Blood Sugar ◽  
Diurnal Cycle ◽  
Blood Sugar Level ◽  
Reducing Sugar ◽  
The Hours ◽  
Slight Rise ◽  
Relationship Of ◽  
The Relationship ◽  
Appreciable Variation

1. The presence of a variation in the mitotic activity of the ear epithelium of normal mice between the hours of 10 a.m. and noon has been demonstrated, in accordance with the ‘diurnal cycle’ found by other workers. An attempt to correlate this with alteration in the level of reducing sugar in the blood has failed, since this level showed no appreciable variation between 10 a.m. and noon. 2. Efforts to influence either the blood-sugar level or the mitotic activity by injecting starch subcutaneously failed to produce any effect. Injection of glucose produced some slight rise in the blood-sugar level, but did not influence the mitotic activity. 3. It is suggested that, while an adequate supply of carbohydrate is probably necessary for the mitotic process, the diurnal cycle may normally be controlled by nervous or hormonal influences.

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