The interaction of stressors in the induction of increased levels of fluctuating asymmetry in the laboratory rat.

Recent studies on fluctuating dental asymmetry have isolated single stressors as causative agents. Since most stressors are composite in nature, the present study was designed to determine the effects of the interaction of stressors in the induction of fluctuating dental asymmetry. Pregnant rats were assigned to one of six treatment groups and stressed with various combinations of heat, cold, noise and protein deprivation. The levels of fluctuating dental asymmetry were assessed and it was found that all protocols produced higher levels of asymmetry than found for control animals. Noise and reduced protein exhibited an additive effect and the interaction of stressors produced a reduction in litter size. Suggestions were offered for further research in this expanding field.