Influence of Fighting on Leukemia in Mice.

In AK mice, males that were isolated early in life and did not fight died of spontaneous leukemia at essentially the same age and in the same proportion as females, whereas fighting males died significantly later and in a lower percentage, so the difference between sexes is not explained by sex hormones only.

Abstract

1) In leukemic strains of mice, lymphoid leukemia is known to occur less often and later in males than females. However, in our AK mice, males that were isolated early in life and did not fight died of spontaneous leukemia at essentially the same age and in the same proportion as females, whereas fighting males died significantly later and in a lower percentage. Hence the difference between sexes is not explained by sex hormones only. An interpretation is proposed, based on adrenal corticosteroid secretion. 2) Fighting activity should be taken into account as a factor in pathogenesis of mouse leukemia and in the difference of incidence and survival time between male and female mice.