American Journal of Clinical Nutrition, Vol 19, 99-104, Copyright © 1966 by The American Society for Clinical Nutrition, Inc.

Plasma Amino Acids in Full-Term Infants

¹ From the Children's Hospital Research Foundation and Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio

Phenylalanine, proline, histidine, valine and leucine-isoleucine were measured in 0.10 ml. samples of plasma from full-term infants weighing over 5 pounds at birth. Specimens were obtained on the day of discharge from the hospital when the infants were two to ten days old. High levels of phenylalanine tended to occur in younger children, and infants whose birth weights were low had higher levels of phenylalanine than those who were heavier at birth, although the latter correlation was not significant. Plasma levels of proline, valine and leucine-isoleucine were significantly higher in infants fed formulas than in breast-fed infants. Values measured by paper chromatographic technics compared favorably with those reported by other investigators who used ion exchange chromatography.