Effect of Housing Conditions on Corticosterone Levels in Mice

Abstract

The levels of peripherally circulating serum corticosterone in groups of mice selected from a common pool and treated identically in all respects except that of housing, are used as a measure of population pressure. Groups of 15 males, 4 to 5 weeks old, when exposed to an established population of 400 mice of both sexes and all ages postweaning showed significantly higher levels of serum corticosterone than cohorts segregated by age and sex in groups of 15. Similarly, body weights of mice exposed to the populations for a one-week period were significantly lower than those of mice housed under control conditions. These observations are indicative of the increased stress encountered by animals exposed to the environmental conditions of large mouse populations.