MITOSENPERIODIK IN DER NEBENNIERENRINDE, SCHILDDRüSE, IM DUODENAL- UND MUNDHöHLENEPITHEL DER RATTE

Mühlemann, H; Marthaler, T; Rateitschak, Klaus H.

doi:10.1159/000141150

Cited by 16 publications

References 22 publications

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Circadian rhythms in mitotic activity and ³H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

1972

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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.There is a controversy whether epithelial cells in the gut of rodents divide with a circadian frequency. This report based on studies of mitotic index in the rat and mouse duodenum, demonstrates that mitosis and the total uptake of 3H-thymidine into the rat duodenum fluctuate over the 24-hour time period. The phasing of the mitotic rhythms and 3H-thymidine uptake are compared. The reasons for the controversy are discussed.Additional experimental studies in mice demonstrate that isoproterenol affects the rhythm in mitosis; the effect obtained depends on the phase of the mouse circadian system during which the drug is administered. The data demonstrate that conflicting results could be obtained if one fails to consider the circadian variation in mitosis in the mouse duodenum. MATERIALS AND METHODSOne hundred and twenty young, adult male rats averaging 190 15 gm in body weight were used. During the four weeks prior to the study, the animals were housed two to a cage in a room maintained at 23 2 2°C. The room was illuminated artificially from 0600 to 1800 (CST). Rockland rat chow and water were available ad libitum. The room was entered only three times per week (Monday, Wednesday and AM. J. ANAT., 135: 311418.

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Circadian rhythms in mitotic activity and ³H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

1972

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Chronobiology of the intestinal tract of the mouse

Scheving

Tsai

1983

Am. J. Anat.

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This paper summarizes recent and continuing work on circadian rhythms in the alimentary tract of rodents; these include: (1) cell proliferation, (2) activities of intestinal enzymes, and (3) behavioral aspects of spontaneous feeding and drinking. All regions of the intestinal tract show marked circadian behavior in cell proliferation. The roles of the light-dark cycle and meal timing in synchronizing such rhythms are discussed as well as the influence of epidermal growth factor, insulin, glucagon, and ACTH 1-17. Attention is called to the potential importance of these rhythms to basic research and medicine. Other circadian rhythms in the alimentary tract are reviewed briefly, such as those characterizing a host of intestinal enzymes, monosaccharide transport, and the height and width of the villi. Many of these have been shown to be cued to a feeding schedule; however, a number of the enzyme rhythms persist for one or two cycles in fasting animals, and this also is the case for the cell-proliferation rhythms. After having been acclimated to a circadian feeding schedule (within a range of 23-30 hr), rodents can on subsequent days anticipate the food an hour or more prior to its arrival. Some enzymes behave in a similar manner in that their activities increase prior to the expected intake of the daily food. These anticipatory response rhythms are under endogenous control, since both will persist in the fasted animal and both will free run when a mouse is placed under constant conditions. Somehow these animals are able to measure circadian intervals of time. This challenges the concept that the oscillations seen in enzyme activities are simply a passive consequence of feeding and fasting, respectively.

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Circadian variation in cell division of the mouse alimentary tract, bone marrow and corneal epithelium

et al. 1978

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Circadian rhythms in DNA synthesis are described for the tongue epithelium, five different regions of the alimentary canal (gut)--esophagus, stomach, duodenum, jejunum and rectum--and bone marrow in a group of BDF1 male mice. A circadian rhythm is also described for the mitotic index in the corneal epithelium in the same mice. The data document for the first time in the same animals the dramatic variation in cell division encountered from one region of the gut to another. This variation is seen in the amplitudes of the rhythms as well as in the over-all 24-hour means. On the contrary, the phasings of the rhythms in the different regions of the gut are remarkably similar. In this study, where the mice were standardized to 12 hours of light (0600-1800) alternating with 12 hours of darkness, the peak of the DNA-synthesis rhythm occurred around the time of transition from dark to light, and the trough around the time of transition from light to dark. The implications of these findings, and those of others, to the study of cell kinetics and to cancer chemotherapy are discussed.

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MITOSENPERIODIK IN DER NEBENNIERENRINDE, SCHILDDRüSE, IM DUODENAL- UND MUNDHöHLENEPITHEL DER RATTE

Cited by 16 publications

References 22 publications

Circadian rhythms in mitotic activity and ³H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

Circadian rhythms in mitotic activity and ³H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

Chronobiology of the intestinal tract of the mouse

Circadian variation in cell division of the mouse alimentary tract, bone marrow and corneal epithelium

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MITOSENPERIODIK IN DER NEBENNIERENRINDE, SCHILDDRüSE, IM DUODENAL- UND MUNDHöHLENEPITHEL DER RATTE

Cited by 16 publications

References 22 publications

Circadian rhythms in mitotic activity and 3H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

Circadian rhythms in mitotic activity and 3H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

Chronobiology of the intestinal tract of the mouse

Circadian variation in cell division of the mouse alimentary tract, bone marrow and corneal epithelium

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Circadian rhythms in mitotic activity and ³H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm

Circadian rhythms in mitotic activity and ³H‐thymidine uptake in the duodenum: Effect of isoproterenol on the mitotic rhythm