Bone turnover in Paget's disease: biochemical and kinetic measurements during salmon calcitonin therapy.

A comparison of calcium-47 kinetics and biochemical measurements has been made in 25 previously untreated patients with Paget's disease. The rate of disappearance of 47Ca into bone with a turnover time of more than 5 days was measured as A5, and the pool size with a turnover time of less than 5 days as E5. In moderately active disease the reductions in A5 and E5 to be anticipated from treatment seem to be offset by an increase in exchangeability due to remineralization of osteoid. In more active disease the effect of calcitonin may be to shift bone formation from a woven to a lamellar pattern as well as to reduce turnover. Under these circumstances both A5 and E5 are reduced by treatment more in keeping with biochemical changes.