## Abstract Circadian rhythms are demonstrated in the tongue of adult rats for both the mitotic index of the basal epithelium and the uptake rate of injected 3Hβthymidine by the tongue tip. The animals were entrained to a lightβdark cycle for four weeks prior to the experiments with the light phase
Circadian rhythms in mitotic activity and3H-thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm
β Scribed by Scheving, Lawrence E. ;Burns, E. Robert ;Pauly, John E.
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1972
- Tongue
- English
- Weight
- 541 KB
- Volume
- 135
- Category
- Article
- ISSN
- 0002-9106
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β¦ Synopsis
Mitotic activity in the duodenum of the rat and mouse exhibits a circadian periodicity with a peak in the rat between 1200 and 1500 hours and a sustained trough between 1800 and 0600. Scintillation counts revealed a similar rhythm in the total uptake of 3H-thymidine by the rat duodenum with a sustained but fluctuating crest occurring between 0800 and 1800 and a trough between 1900 and 0100. In the mouse the peak mitotic activity occurred at 0900 and the trough at 1700. Isoproterenol completely abolishes the rhythm in mitosis in mouse duodenum, when injected exactly 28 hours previous to sacrifice. The results are discussed in relation to reports that deny a circadian rhythm in mitotic activity in the duodenum.
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