[A sensitive fluorimetric method of determining tryptophan hydroxylase activity of structures in the brain].

An assay of tryptophane hydroxylase activity in brain was based on fluorometric measurement of serotonin after condensation with o-phthalic aldehyde in 10 N HCl. The method proved to be more sensitive and simple as compared with the previously reported technique and enabled to measure the enzyme activity in brain samples as little as 10 mg. The method is recommended for laboratory routine use.