Response of vitamin D metabolites to calcium restriction in hypercalciuric renal lithiasis.

: A group of patients with hypercalciuric renal lithiasis and a group of controls underwent dietary calcium restriction, reinforced by cellulose phosphate, during two weeks. Before and after that intervention, serum levels of 25 OH D, 1.25(OH)2D and PTH, and urinary excretion of cAMP and hydroxyproline were measured. Although the baseline 1.25(OH)2D level was higher in patients with stones, it did not increase with diet as it was the case with controls. Also, the urinary excretion of cAMP was increased in controls but not in patients. 25 OH D, PTH and hydroxyproline were not changed. We conclude that dietary calcium restriction in patients with hypercalciuric renal lithiasis does not appear to induce hormonal changes potentially damaging for the bone.