Determination of the Plasma Glycine after Gelatin Feeding as a Diagnostic Procedure for Pancreatic Fibrosis.

A retardation of the absorption of amino acids derived from ingested protein into the bloodstream is known to result from a failure of the secretion of the pancreatic proteinases. West, Wilson and Eyles (1) have shown that a much smaller rise in blood amino nitrogen occurs in children with pancreatic fibrosis than in normal children after a test meal of casein. Preliminary results obtained by these authors indicated that gelatin might be a better test protein. To avoid a choice between the technically somewhat complex manometric ninhydrin procedure (Hamilton and Van Slyke [2]) and the analytically unsatisfactory colorimetric amino nitrogen methods (cf. Chinard and Van Slyke [3]) we have determined the plasma concentration of the single amino acid, glycine. Advantage is taken of the convenient method available for glycine (Alexander, Landwehr and Seligman [4]), the high glycine content of gelatin (25.5%), and the relatively slow disposition of this amino acid. Comparison of the fasting plasma glycine with the level 150 minutes after gelatin feeding provides a simple diagnostic procedure, although some qualifications will be noted below. Although duodenal intubation in most cases is not a difficult procedure, upon occasion it may be troublesome. Mention might be made of a) several instances where four or five separate unsuccessful attempts were made to obtain a satisfactory specimen from a patient, b) the undesirability of the procedure in the severely ill infant, and c) the occasional febrile reaction following intubation. The present procedure offers an alternative diagnostic test.