ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Three groups of mice were standardized to a light-dark cycle with light from 0600 to 1800. One group was fed ad lib; but the other two had access to food for only four hours a day, one during the first part of the light phase and the other beginning at its middle. Two other groups were subjected to a reversed light-dark cycle (light from 1800 to 0600); one of these had access to food for four hours during the first part of the dark phase and the other for four hours beginning at its middle. All the mice previously had been adjusted gradually over a three-week period to these feeding schedules, and then they were maintained on the precise routine described for an additional two weeks. After standardization was completed, subgroups of mice were killed at three-hour intervals over a single 24-hour period. Corneas were removed and prepared, and the mitotic index in the epithelium was evaluated.In all five groups a high-amplitude circadian rhythm was found for the mitotic index, but in all cases this rhythm remained synchronized to the light-dark cycle; only small changes in the phasing of the rhythm resulted from the restricted feeding. These results are contrary to what has been found for a number of other rhythmic variables which do synchronize to such feeding schedules.The findings dispel the misconception that all body functions react in the same fashion to different synchronizors and emphasize that one must not generalize about the effects of feeding or lighting.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091800106
Permalink
