EFFECT OF GROUP SIZE, SEX AND TIME ON ORGAN WEIGHTS, CATECHOLAMINES AND BEHAVIOR IN MICE

Male and female mice were subjected to isolation and excessive overcrowding for 1-week and 4-week periods to determine [1], what effect population density would have on organ weights and catecholamines in relationship to behavioral changes, and [2], in what manner time might influence these interactions. The only consistent significant physiologic and biochemical effects were sex-related and were not modified by changes in the environment. However, fighting behavior, a sex-related characteristic that was only elicited in the male mice, required a change in the environment, i.e. isolation, to be expressed. Thus, no measurable biochemical effect could be associated with a change in behavior. © 1969.