Tryptophan Metabolism in Senile Cataract Patients Assessed by High-Performance Liquid Chromatography
In 1975, it was suggested that a relationship may exist between the development of senile nuclear cataract and the metabolism of tryptophan (Ogino and Ichihara, 1957). Two metabolites of tryptophan, anthranilic acid and 5-hydroxyanthranilic acid, were isolated from the urine of patients with cataractous lenses. The oxidation product of 5-hydroxyanthranilic acid was demonstrated to initiate cataract formation. In 1977, anthranilic acid was isolated from the proteolytic digest of cataractous lens protein, but not from normal lenses (Truscott et al., 1977). The authors suggested that the anthranilic acid was derived from protein-bound tryptophan. In the 1980’s, some controversy arose as to the status of plasma tryptophan in senile cataract patients (Cotlier and Sharma, 1980; Allegri and Angi, 1981; Chadwick et al., 1981; Cotlier and Sharma, 1981; Allegri. et al., 1984; Augusteyn et al., 1987), but the findings were consistent with the idea that cataract patients may metabolize tryptophan differently after a meal or a tryptophan load.
KeywordsAqueous Humor Anthranilic Acid Kynurenic Acid Tryptophan Metabolism Xanthurenic Acid
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