Increased Concentrations of 3‐Hydroxykynurenine in Vitamin B 6 Deficient Neonatal Rat Brain

Increased concentrations of the endogenous tryptophan metabolite 3‐hydroxykynurenine (3‐HK) were measured in the brains of vitamin B 6 deficient neonatal rats. Mean concentrations of 3‐HK in B 6 deficient cerebellum, corpus striatum, frontal cortex, and pons/medulla ranged from 9.7 to 18.6 and 102 to 142 nmol/g of wet tissue at 14 and 18 days of age, respectively. 3‐HK was not significantly increased in control neonatal or adult rat brain, vitamin B 6 deficient rat brain at 7 days of age, or in brains from adult rats deprived of vitamin B 6 for 58 days. The administration of daily intraperitoneal injections of vitamin B 6 from the 14th to the 18th day of age decreased the concentration of 3‐HK to control levels. 3‐HK has been shown by other investigators to produce seizures when injected into the cerebral ventricles of adult rodents. Thus, our studies show the accumulation in brain of a putative endogenous convulsant as the result of a nutritional deficiency.