Glucose metabolism in patients receiving chronic calcitonin treatment

The effect of long term (two months) administration of synthetic salmon calcitonin (100 MRC Units per day) on plasma glucose, insulin, C-peptide, glucagon and growth hormone responses to iv glucose and arginine were investigated in patients with either Paget's disease of bone (n = 6) or significant osteoporosis (n = 9). Glucose tolerance did not deteriorate after treatment, despite a reduction in the early insulin response to glucose, resetting of the C-peptide response at a lower level and a reduction in glucose-mediated glucagon suppression. The rise in plasma glucose triggered by arginine was reduced after treatment despite similar hormonal environment. This seems to suggest a positive influence of calcitonin on glucose disposal. The diabetogenic action of acute calcitonin administration is not observed after prolonged administration of the hormone. However, the possibility that calcitonin may produce a diabetic state in subjects with decreased insulin reserve cannot be totally exclused.