[Citric acid excretion in stone-formers and healthy controls on normal and standard diet (author's transl)].

The citric acid excretion and concentration in 24 hours urine was measured in 70 stone-formers and 16 normal subjects (controls) on normal food intake followed by 9 days on a standard diet. On days 9 and 10 on the standard diet urine was collected in 3 hours portions and citric acid and calcium was measured. From day 7 to day 10 on standard diet we found only a slight change in the 24-hour excretion of citric acid ("steady state"). The citric acid excretion and concentration is significantly lower in stone-formers than in healthy controls. In both groups there is a sinusoid rhythm in citric acid excretion and concentration throughout the 24 hour period. The calcium concentration is at its maximum when the citric acid concentration is at its minimum.