Suppression of pimozide-induced prolactin secretion by piridoxine (vitamin B6).

I.V. administration of 300 mg. Pyridoxine caused an acute fall in prolactin (PRL) plasma levels in six normal subjects. Like levodopa, pyridoxine suppressed the increase in PRL secretion induced by treatment with pimozide, a specific dopamine receptor blocking agent. These findings further support the hypothesis that vitamin B6 stimulates dopaminergic activity at hypothalamic and/or hypophyseal level.