Diets containing 5.0% excess phenylalanine; 6.0% excess protein (gelatin), and limited in tryptophan (75mg/lOOg) and/or vitamin E (O.lmg/IOOg) were fed to male rats during gestation and lactation. Addition of 5.0% phenylalanine result in a greater incidence of cataract than studies previously reported with diets limited in tryptophan and vitamin E alone, or a single supplementation of Vitamin E (40.0.mg/lOOg). Supplementation with tryptophan (500mg/lOOg) and vitamin E (40.0mg/100g) prevented cataract formation. Replacing the 5.0% excess phenylalanine and 6.0% excess protein (gelatin) with an equivalent of a balanced free amino acid mixture prevented cataract formation in the group supplemented with vitamin E alone. Addition of balanced free amino acids resulted in decreased fertility, pup survival, and increased diuresis. Supplementation with vitamin E (40.0mg/lOOg) alone prevented these effects. Urinary excretions of keto acid (phenylpyruvate), nitrogen, urea, and creatinine were examined during the 7-l4th days of gestation. Amino acid analysis were performed on plasma and soluble lens hornogenates from young progeny. Protein separations of soluble lens homogenates from young progeny were obtained. Analysis of these parameters did not indicate distinct differences between cataractous and noncataractous groups. / Master of Science