The pathophysiology of calcitonin in man

It is generally accepted that calcitonin (CT) induces a decrement in cytosolic Ca++, and an increase of cAMP in target cells of several organs and tissues. This happens particularly in bone, where osteoclast activity and size decreases, along with the widely-known hypocalcaemic and hypophosphoraemic effect of the hormone. The physiological role of CT appears to be of importance in pregnancy and perhaps in infancy, when it antagonizes possible excessive bone loss. Some experimental evidence shows that CT may be involved in the maintenance of post-meal calcaemia. It is not yet established whether paucity of CT plays any important role in the pathogenesis of pathological conditions such as post-menopausal and senile osteoporosis.