Alteration of serum tryptophan metabolism in patients suffering from senile cataract.

In vitro experimental evidence suggests tryptophan (TRP) is involved in protein modifications which could cause cataract formation in vivo. Previous studies of tryptophan plasma and serum metabolism are conflicting. In this study free and bound TRP plasma levels were measured in patients with senile cataract and in controls after an oral load of L-TRP (20 mg/kg b.w.). Free TRP levels were higher in patients than in controls one hour after L-TRP administration.