[Renal calcium excretion in primary hyperparathyroidism and idiopathic hypercalciuria (author's transl)]

The tubular reabsorption of calcium is increased in primary hyperparathyroidism as compared to control subjects and patients with resorptive hypercalciuria. The mean percentage of filtered calcium being reabsorbed by the renal tubules is decreased in primary hyperparathyroidism and hypercalciuria. This might point towards a maximal tubular transport capacity being exceeded in some cases of primary hyperparathyroidism whereas a relative hypoparathyroidism with decreased stimulation of tubular calcium reabsorption might be involved in hypercalciuria.