Feeding conditions and estrous cycle of female rats under the activity-stress procedure from aspects of anorexia nervosa.

The present study investigated the application of female rats with activity stress as an animal model for anorexia nervosa. Young female rats were singly housed in activity-wheel cages with food-restricted schedule (2, 3, or 4 h of food availability per day) for 3 weeks. Estrous cycle, body weight, food intake, and wheel revolution were recorded daily. Gastric pathology was also observed using the endoscopic technique. Rats that were subjected to either a 3- or 4-h feeding schedule exhibited the cessation of estrous cycle, loss of body weight, and suppression of food intake. These animals also showed a remarkable increase in running activity. However, they had no gastric lesions throughout the experimental period. On the contrary, the 2-h feeding schedule elicited severe gastric lesions and high mortality. The results suggest that behavioral and physiological changes of the young female rats with 3 or 4 h feeding share some symptoms of anorexia nervosa, although their anorexia is not self starvation.