Magnitude of Urinary Iron Excretion in Healthy Men

Abstract

Henriques and Roland 1 have found that the daily excretion of iron in the urine of both normal and pathological cases is very small, amounting to only 0.08 to 0.32 mg. These values are much lower than those reported by earlier workers. Lintzel, 2 however, has claimed that not more than 0.02 mg. of iron per liter can be found in normal urine. Likewise, other investigators 3 have found the urine of patients suffering from various diseases to be practically iron-free. Because of its bearing on problems relating to the metabolism of iron we have investigated anew the question of the magnitude of the urinary iron excretion.

The urine was obtained in clean bottles from male subjects who were pursuing their usual routine in the laboratory. In brief, the analytical procedure consisted of the following steps: A measured volume, usually 500 cc, of the fresh 24-hour urine specimen was evaporated to dryness in a silica dish, and then incinerated in an electric furnace at about 500° C. for 8 hours. The ash was dissolved in dilute HC1, brought to a volume of 50 cc, and aliquot portions were removed for the determination of iron by the thio-glycolic acid method. 4

The analytical technic was subjected to repeated tests and found to be adequate. All reagents were shown to be free from iron. Small quantities of iron added to urine were quantitatively recovered, proving that iron was not lost in the manipulations. Finally, a solution of pure substances was prepared in imitation of the main constituents of urine and this solution was evaporated, ashed, and analyzed for iron. None could be detected, proving that the iron found in the analyses was not due to contamination.