n-hexane induces parkinsonism in rodents.

A case of human parkinsonism, due to n-hexane exposure, was recently described. On the basis of this observation, we treated mice and rats with n-hexane and its principle toxic metabolite 2,5-hexanedione. The mice underwent a chronic treatment intraperitoneum, the rats were treated stereotaxically into the substantia nigra. At biochemical analysis of the striata, dopamine and homovanillic acid levels were significantly lower compared with control animals; norepinephrine, serotonin, 5-hydroxindolacetic acid levels were unchanged. The rats treated with 2,5-hexanedione showed an apomorphine-induced rotational behavior significantly higher compared to controls. Since n-hexane and its metabolites are environmental contaminants and by-products of endogenous metabolic pathways, we propose that they may play a role in inducing parkinsonism in humans.