Absence of a circadian rhythm in crypt cell mitotic rate following chemical sympathectomy in rats.

The circadian rhythms in both consumption of food by rats and in the mitotic rate in epithelial cells lining the bases of the crypts of Lieberkühn of the proximal jejunum were studied in normal and in chemically sympathectomised rats. In normal rats both food consumption and crypt cell mitotic rat showed a distinct circadian rhythm, both parameters having a peak around 00.00 to 04.00 hours. Following chemical sympathectomy the circadian rhythm in food consumption was essentially unchanged whereas that in the crypt cell mitotic rate was abolished.