[Comparative effects of oral water load of different mineral compositions on the excretion of ions and oxalic acid].

The effects on urinary excretion of a 1500 ml daily load of three drinking waters with different ionic contents were studied in six normal subjects. Diuresis was similarly increased by the three waters of an amount equal to the load. Urine output of urea, creatinin, uric acid, phosphate, potassium, magnesium was not significantly modified by the three waters as compared to a control period. Natriuresis was significantly increased following the intake of the water which contained sodium as well as calciuria with the water containing calcium. Urine output of oxalate was increased by the three waters in correlation with the free water content of the load. This effect is probably due to a reduction in passive tubular reabsorption of oxalate since a similar effect was observed with an equivalent water load given by intravenous route. Nevertheless, due to the dilution of urine, the index of urine saturation for calcium oxalate was diminished by the three waters.