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Calcitonin secretion in idiopathic renal stone formers
Author(s) -
Fuss Michel,
Pepersack Thierry,
Corvilain Jacques,
Bergmann Pierre,
Simon Jacques,
Body JeanJacques
Publication year - 1991
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650060107
Subject(s) - medicine , endocrinology , calcium , hydroxyproline , calcitonin , basal (medicine) , bone resorption , radioimmunoassay , excretion , chemistry , alkaline phosphatase , resorption , bone remodeling , urine , enzyme , biochemistry , insulin
Several studies demonstrated a reduction in bone mineral content (BMC) in idiopathic renal stone formers (RSF). We found this reduction in association with a chronic low‐calcium diet. Low calcium intake could theoretically result in calcitonin deficiency, responsible for increased bone resorption. This hypothesis was tested in 22 male RSF eating a low‐calcium diet (350 ± 72 SD mg/day) for 2 years or more, who showed a significant reduction in their BMC. When compared to 15 normal male subjects eating a free diet, RSF showed increases in serum alkaline phosphatase activity and fasting urinary excretion of hydroxyproline and calcium, suggesting increased bone turnover. Plasma calcitonin levels were measured by radioimmunoassay following an extraction‐concentration technique (exCT). Basal plasma exCT levels were higher ( P < 0.005) in RSF (4.1 * 0.8 SEM pg/ml) than in normal subjects (2.8 ± 0.4). Following a 5 minute infusion of 2 mg elemental calcium per kg, levels of plasma exCT tended to increase more, although not significantly, in RSF (51.3 ± 9.4 pg/ml) than in normal subjects (36.6 ± 9.7). The CT secretory response, taking into account changes in serum calcium concentration (AexCT/ACa), was higher ( P < 0.05) in RSF (50.0 ± 10.0) than in normal subjects (25.6 ± 6.6). Our study thus demonstrates that RSF chronically fed a low‐calcium diet have increased basal plasma CT levels and increased CT cells responsiveness. CT deficiency cannot therefore be considered a cause for the low BMC associated with a chronic low‐calcium diet in RSF.