title: Circadian rhythms of mitotic activity in gastric mucosa of feeding and fasting rats.
abstract: The mitotic index of the glandular epithelium of gastric mucosa was studied in fasting and feeding rats. Fifty-four adult Wistar (ICB) rats, both males and females, were randomly divided into two groups of 27, and one of the groups was fasted for 26-34 hr. All rats were kept on an LD 13:11 cycle with natural light from 0530 to 1830 hr. Eight groups of three or four rats each were killed at 3-hr intervals commencing at 0900 hr. All animals were injected intraperitoneally with colchicine, 1 mg/kg body weight, 2.5 hr before sacrifice. At least 5,000 cells were counted per animal in 5-micron sections. The proportion of colchicine-arrested metaphases in the proliferative zone was determined and expressed as a percentage. The animals fed ad libitum showed a peak of mitotic index at 1200 hr and a trough at night. From the single cosinor analysis, a 24-hr rhythm was detected with the following values: amplitude = 1.40, mesor = 1.47, acrophase = -194.7 degrees, and P = 0.010. The fasting rats exhibited lower values of mitotic index but still a peak at 1200 hr. However, the single cosinor analysis did not show a 24-hr rhythm; values were amplitude = 0.36, mesor = 0.73, acrophase = 142.3 degrees, and P = 0.679.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D004247:DNA / Q000096:biosynthesis; D004435:Eating; D005215:Fasting; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology* / Q000378:metabolism; D008297:Male; D008940:Mitotic Index; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors
chemical_list: D004247:DNA