[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 observed for 3-minute periods with an interval of 20 days. The mean scores 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 diabetes (DM) in female mice were observed after 120 days old. After the 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. These data suggest that conspicuous weight loss with the expression of overt diabetes in NOD female mouse might correlate to decrease of the ambulation and rearing scores.