Effects of physical restraint on leukemogenesis by Friend virus.

The effects of physical restraint on the development of Friend erythroleukemia in ddY mice were examined. Restraint was applied by immobilizing the mice in wire cages. In both sexes there was a reduction in the weight of the whole body, thymus and spleen, though the food intake was not reduced. The incidence of leukemia was reduced in the males, but not in the females, while the latent period was prolonged in both sexes. This sex dependency is characteristic of the stress response.