Variable effects of vitamin E on Drosophila longevity.

Vitamin E has been used widely in invertebrate experiments where it usually acts to prolong life span. Conversely in vertebrates it has been less successful. In some cases, experiments in rodents show no effect of vitamin E on longevity. Consequently, the suggestion has been made that anti-oxidants do not effect ageing in vertebrates. In more extensive experiments with Drosophila melanogaster, vitamin E exerted both life span extending and toxic effects. At 20 micro g/ml, the life span was increased by 16%, although there was no effect at higher or lower concentrations. At 200 micro g/ml, vitamin E protected Drosophila against paraquat toxicity. At this concentration, vitamin E had no effect on longevity in one set of experiments, and shortened the life span in another set. Apparent toxicity of vitamin E was also observed in behavior experiments. We suggest that inactivity of vitamin E that has been reported by some authors is due to antagonistic actions of a toxic effect and a beneficial anti-oxidant action. This complex response to vitamin E will limit its use for clinical and investigative work on ageing.