| Abstract: | The changes which occur in both calcium and citrate excretion in normal persons, in idiopathic calcium stone formers and in persons with hyperparathyroidism have been measured at high and low levels of dietary calcium intake. The findings suggested a difference in the renal handling of calcium between normal subjects and stone formers. There was a greater increase in the urinary excretion of calcium with increased intake of calcium in individuals with renal calculi than in normals. Increasing the calcium intake shifted the mole ratio of calcium to citrate unfavourably for the chelation of calcium by citrate, and this unfavourable shift was more marked in the stone formers than in normal individuals. These findings support the concept that urinary citrate may be of importance in the prevention of calcium precipitation and hence in the pathogenesis of kidney stones. |
