Serum immunoreactive calcitonin concentration (iCT) was determined in nine subjects with idiopathic hypercalciuria (IH), prior to and during oral phosphate supplementation (500 mg qid) to test the hypothesis that a renal phosphate leak was the primary defect resulting in IH in these patients. Prior to the oral phosphate supplementation, serum ICT was significantly elevated in the IH group, when compared to 26 normal individuals (75 ± 7 vs 45± 4 pg/ml, mean ± SE, P < .001). During oral phosphate treatment, however, serum iCT decreased to levels not significantly different from normals (39 ± 3 and 50 ± 5 pg/ml after 4 and 8 weeks, respectively). When data prior to and during phosphate supplementation were pooled, there was a significant correlation (r = .70, N = 26, P < .001) between serum iCT and serum calcium. These observations suggest that the increased serum iCT in these subjects was a response to slight elevations in serum calcium, which are the result of normal physiological mechanisms to correct the renal phosphate leak.
- Idiopathic Hypercalciuria
- Oral Phosphate
- Renal Phosphate Leak
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism