BEHAVIORAL-CHARACTERISTICS OF OPEN-FIELD ACTIVITIES IN NOD MICE

The open-field test was carried out on NOD mice of both sexes between the ages of 40 to 300 days. The behavior of both sexes of mouse was ob served for 3-minute periods with an interval of 20 days. The mean scor es of ambulation and rearing increased at the ages of 40-80 days old, and both scores decreased more than 100 days old. The onset of overt d iabetes (DM) in female mice were observed after 120 days old. After th e onset of DM with great loss of body weight, the scores of ambulation and rearing were dramatically decreased. Other parameters, urination, defecation, and preening were not changed with age of both sexes. The se data suggest that conspicuous;weight loss with the expression of ov ert diabetes in NOD female mouse might correlate to decrease of the am bulation and rearing scores.