Serum parathyroid hormone and calcitonin levels in racehorses with fracture

Serum parathyroid hormone (PTH) and calcitonin (CT) levels in fractured rac ehorses were measured by radioimmunoassay. Racehorses with fracture of larg e bone such as the radius, third metacarpus, third carpus, digital bone or tibia, showed normal PTH level and elevated CT level in the serum. Serum PT H level was slightly higher in racehorses with sesamoid bone fracture compa red to that of healthy racehorses, but not statistically significant. Moreo ver, serum CT level of racehorses with sesamoid bone fracture was significa ntly higher than that of healthy racehorses. Racehorses with sesamoid bone fracture and large bone fracture might be in different conditions of calciu m regulation.