[Different behavior of bone turnover markers in endocrine (extrinsic) and structural (intrinsic) osteopathies]

Alkaline phosphatase, osteocalcin and hydroxyproline levels were evaluated in patients with the following conditions: primary hyperparathyroidism, renal dialysis, hyperthyroidism, Cushing's syndrome, long term corticosteroid therapy, Paget's disease, osteoblastic metastases, osteolytic or mixed metastases, and nutritional osteomalacia. In all cases the levels of the three substances were increased, with the following exceptions: a) in endogenous or exogenous hypercortisolism states osteocalcin level was reduced and those of alkaline phosphatase and hydroxyproline were unchanged; and b) in blastic or lytic metastases osteocalcin level was unchanged. In general, alkaline phosphatase and hydroxyproline levels had a higher sensitivity than those of osteocalcin in structural bone disease (Paget's disease, blastic or lytic metastases), whereas the converse was true for endocrine bone disease (the remaining conditions except osteomalacia, which is mixed, both structural and endocrine; in this syndrome, the three substances showed the same sensitivity.