ABSTRACT
The effect of fasting on cell proliferation in the gastric mucosa was investigated in 14-day old suckling Wistar rats. The renewal of the epithelial cells of the corpus of the stomach was evaluated by DNA labelling and counting arrested metaphases in fifty 14-day old rats fasted for 18 to 21 h and in fifty 14-day old rats fasted for 18 to 21 h and in fifty control suckling rats of the same age. The animals were sacrificed at 3 h intervals over a 24-h period. The metaphase arrest method was also used to estimate the rate of entry of cells into mitosis in the gastric glands of 26 rats under both feeding and fasting conditions. In addition to the proliferation indiices, the number of epithelial cells, and the heights of the glands and mucosa were measured morphometrically in 20 rats. No significant differences in the rate of entry of cells into mitosis (number of cells in fasted = 0.49 ñ 0.077 cells 100 cells -1 h-1), in the number of epithelial cells (fasted = 241.2 ñ 24.3 cells/0.023 mm2) or in the height of the gastric glands (fasted = 194 ñ 5.4 um) of fasted and control rats were observed. Both labelling and metaphase indices (means ñ SEM) were significantly higher (P<0.01) in the fasted (13.9 ñ 0.57% and 1.3 ñ 0.07%, respectively) suckling rats than in the controls (7.9 ñ 0.39% and 0.9 ñ 0.05%, respectively). These data indicate that fasting stimulates cell proliferation in the gastric mucosa of suckling rats rather than decreasing proliferation, as the case for adult rats