Urinary Excretion of Amino Acids by Subjects with Renal Calculi

Abstract

Idiopathic calcareous calculi remains a disorder of unknown cause, or causes. However, this affliction occurs predominantly in nonblack men, is affected by undefined geographic or climatic factors, and may be influenced by dietary habits¹. In addition, the familial occurrence of idiopathic calculi has suggested that hereditary factors may exist that increase susceptability to this disorder². Searching for a possible index of renal tubular dysfunction, McGeown³ investigated the amino acid excretion of 110 patients with calcareous calculi. She reported that, except for 30 patients with some increase in urinary cystine, the amino acid excretion was reduced in the calculous patients as compared with the amino acid excretion of normal subjects. Of these 110 patients, twenty-three had hyperparathyroidism and the mean excretion of amino acid nitrogen was less in these than in the group as a whole. Subsequently, Hum and associates⁴ reported the urinary amino acid values of 15 patients with calcareous calculi, but they found a reduced excretion only in those patients with impaired renal function.