Effect of vitamin E deficiency on rat brain monoamine metabolism

We investigated the effects of vitamin E deficiency on the monoamine metabo lism in the rat brain. Male Wistar rats fed on the vitamin E deficient diet for 24 weeks were analyzed. At 28 weeks, they showed a reduced growth rate (52% of reduction), muscle atrophy, a motor weakness of hind limbs and dis turbance of gait. The concentrations of monoamines, their precursors and me tabolites in the brain were simultaneously determined using high performanc e liquid chromatography (HPLC) coupled with a coulometric detection with el ectrode array system. In addition, tryptophan hydroxylase activity was meas ured. The dopamine (p = 0.009) and serotonin (p = 0.04) levels in the brain stem of vitamin E deficients rats were significantly lower than in the con trols, whereas their precursors tyrosine (p = 0.0009) and tryptophan (p = 0 .0065) levels in the brain stem were significantly higher than in the contr ols. Moreover, tryptophan hydroxylase activity (p = 0.0005) in the brain st em of vitamin E deficient brains was significantly lower than in the contro ls. All statistical comparisons were done using non-parametric tests (Mann- Whitney U test). These results suggest that vitamin E deficiency may play a role in the disturbance of monoamine metabolism in rat brain.