Calcitonin Secretion and Bone Disease Severity in Hypercalcaemic Hyperparathyroidism

Abstract

Calcitonin (CT) plasma levels and urinary hydroxyproline (OHPr) excretion were studied in twenty-eight patients (eleven males and seventeen females) with primary hyperparathyroidism in order to ascertain the effect of CT secretion on the severity of bone disease. The results show that in primary hyperparathyroidism plasma CT levels are increased in about 50% of patients independent of sex. Plasma CT levels were correlated with serum calcium values in males but not in females. Urinary OHPr excretion values appeared higher in those patients which showed lower CT plasma levels. In this latter group the incidence of undetectable CT plasma values was higher in females. The results suggest that in patients with primary hyperparathyroidism the persistent challenge of CT secreting parafollicular cells due to chronic hypercalcemia, may induce a decrease in their functional reserve, and that the bone involvement may have a greater incidence and more severe course in females, due at least in part, for their inability to increase CT secretion as much as males, due to an intrinsic sex-related lower CT secretory reserve.

Could Primary Hyperparathyroidism-Related Hypercalcemia Induce Hypercalcitoninemia?

“…Although most of the authors found normal CT levels [7,8], others have reported basal elevated CT: in about 50% of cases in a series of 28 patients, and in men only from another series of 55 patients [9,10,11]. However, all these studies were done in a small series of patients and used polyclonal CT radioimmunoassays which are not specific of the mature CT monomer, which should explain the reported high CT levels in these series.…”

“…The relationship between CT and hypercalcemia revealed some discrepancies: if an acute increase of serum calcium was clearly demonstrated to stimulate CT secretion, the effect of chronic hypercalcemia on CT secretion remains unclear [2,6,7,8,9,10,11,12]. …”

“…Acute hypercalcemia was shown to increase CT secretion by thyroid C cells, depending on both the calcium concentration and the level of calcium increase, which supports the use of calcium infusion as a stimulating CT secretion test [3,4,5]. On the contrary, the effect of chronic hypercalcemia on CT secretion remained debated: some studies found an increased CT secretion while others did not [6,7,8,9,10,11,12]. However, all these reports were done in small series of patients and have not been reconsidered by using current immunometric CT assays [6,7,8,9,10,11,12].…”

The Effect of High Parathyroid Hormone Concentration on Calcitonin in Patients with Primary Hyperparathyroidism2)

“…Conflicting results, however, have been reported. Some groups found normal basal serum CT concentrations in almost all patients with primary hyperparathyroidism (Deftos et al, 1971;Tashjian et al, 1972;Monta et al, 1975;Adachi et al, 1976;Lambert et al, 1979;Robinson et al, 1982), whereas others found high mean serum CT concentrations (Silva et al, 1974;Heynen and Franchimont 1974;Parthemore 1977;Parthemore et al, 1977;Parthemore and Déftos 1978;Parthemore and Deftos 1979;Mazzuoli et al, 1981). In the present study we have found a negative correlation between CT and PTH in patients with proven primary hyperparathyroidism.…”