Abstract
Urine specimens from Itai-itai patients living in Jinzu River Basin area polluted by cadmium and those from some inhabitants with tubular proteinuria and glucosuria living in Ichi River Basin area where cadmium pollution was found were analyzed for individual free amino acids quantitatively.
Generalized aminoaciduria was found in Itai-itai patients and also in the inhabitants in Ichi River Basin area, and the amino acid patterns were very simililar to each other though the excreted amounts of amino acids were a little lower in urine from the inhabitants in Ichi River Basin area. The aminoaciduria in these cases was very similar in its pattern to that reported in the Fanconi syndrome.
Relationships among the excretions of individual amino acids were observed and it led to the conclusion that the most probable mechanisms of the aminoaciduria in these cases was due to multiple disorders of amino acid transport in renal tubules. The most frequently impaired amino acid transpot system among the inhabitants in cadmium polluted areas was presumably “Neutral I System”, and “Basic System” and “Neutral II System” were less frequently impaired, “Acidic System” was the least. “Beta-amino System” did not seem to be affected.
The amount of increased hydroxyproline excretion was higher than that expected from the renal transport defect. It should be taken into consideration that the imino acid metabolism would be disturbed in these cases.
Further studies to examine amino acids in blood and amino acid clearance in kidney of these cases would be required to confirm these suggestions.
