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Attention has been drawn by Levine, Marples, and Gordon (1) to the relationship between ascorbic acid and the urinary excretion of aromatic amino acid intermediates by the normal premature male infant, both during periods of high protein intake and supplemental tyrosine and phenylalanine ingestion. To our knowledge, no reports have been forthcoming of similar studies with older, ascorbic acid depleted subjects.3 This communication is concerned with the metabolism of l-tyrosine in infantile scurvy. Observations have been made on the urinary excretion products, the serum content of both hydroxyphenyl compounds and amino acid nitrogen.Sealock and his co-workers (2) have demonstrated that the oral administration of l-tyrosine to scorbutic guinea pigs results in the urinary excretion of the amino acid and its two principal deaminated products, parahydroxyphenylpyruvic and parahydroxyphenyllactic acids. A proof that this metabolic disorder is primarily dependent upon the state of ascorbic acid depletion is afforded by the observation that the tyrosyluria (hydroxyphenyluria) is abolished when the vitamin is given orally or parenterally.Certain liver extracts are capable of modifying an induced tyrosyluria ( 1, 3), and recently Woodruff and Darby (4, 5) have indicated that pteroylglutamic acid (PGA) exerts a similar effect in the depleted guinea pig maintained on a basal scorbutogenic diet with supplements of l-tyrosine. By the administration of PGA to normal premature infants, Govan and Gordon (6) established by dietary cow's milk protein. Several in vitro studies on the respiration of liver preparations with tyrosine as a substrate (7-9) tend to confirm that ascorbic acid, PGA, and certain liver fractions are concerned with the complete metabolism of tyrosine.The appearance of alkaptonuria during periods of high aromatic amino acid consumption has been noted in the albino rat (10) and in the scorbutic guinea pig ( 11 ), but the excretion of homogentisic acid by human subjects in a state of ascorbic acid depletion has not been reported.The present investigation is concerned with the effect of ascorbic acid, PGA and vitamin B12, on the urinary and serum tyrosyl content of several infants with clinical and preclinical scurvy during supplemental l-tyrosine feedings. METHODSUrine specimens were collected under toluene and stored at 4°C. Metaphosphoric acid was used in addition to toluene as a preservative when urinary ascorbic acid analyses were undertaken. Blood samples, when required, were obtained by internal jugular puncture approximately one and one-half hours after feeding. The sera were kept frozen until their amino acid nitrogen. and hydroxyphenyl content had been estimated. All colorimetric estimations were made with either a Coleman Junior spectrophotometer or an Evelyn photoelectric colorimeter. 1) Total Urinary Tyrosyl (Hydroxyphenyl) Compounds These were estimated by the method of Folin and Ciocalteau as modified by Medes (12) and adapted to the spectrophotometer at a wavelength of 465 muA. 2) Urinary Tyros...

Erroneous urine tests for sugar can result from many causes. The Clinitest method carried out in the usual recommended way (five drops of urine) is accurate in the 0 to 2 per cent sugar concentration range. Over 4 per cent, there is a reversal of color which can be mistaken for 0.75 or 1 per cent and which is referred to as “pass through.” When two drops of urine are used instead of five, the range of Clinitest change is extended from 0 to 5 per cent and the “pass through” delayed until a concentration over 10 per cent sugar is reached. In 191 urines from diabetic children, the confusing “pass through” was found to occur seventy times when the urine was tested by the “five-drop method.” It did not occur in testing the same urines using the “two-drop method.” Quantitative chemical analysis established the range of these two methods. It is recommended that the “two-drop method” should replace the “five-drop method.”

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