Measurement of turnover of dopamine, noradrenaline and serotonin and their metabolites was assessed in striatum and substantia nigra of adult female rats that were fed control or vitamin E-deficient diets over 15 days. The levels and turnover of dopamine increased and the levels of serotonin decreased in both structures whereas serotonin turnover decreased only in striatum. No change was found in the turnover rate of noradrenaline between control and experimental animals. However, the most striking result was the increase of dopamine turnover found in substantia nigra. This dopamine increase was accompanied by an increase in 3-methoxytyramine turnover which seems to indicate an increase in dopamine release after vitamin E deficiency. The present study indicates that the nigrostriatal dopamine neurons are susceptible to the deficiency of vitamin E. Moreover, these data suggest that substantia nigra may be more susceptible to damage from vitamin E deficiency than striatum.