Parathyroid hormone, calcitonin, and vitamin D metabolites during normal fracture healing in humans. A preliminary report.

The metabolism of calcium is regulated by hormones: parathyroid hormone, (PTH) calcitonin (CT), and vitamin D metabolites. To study the physiologic role of these hormones during the process of fracture healing in humans, the blood levels of PTH, CT, 25-(OH)-D3, 24,25-(OH)2-D3, and calcium were determined in 13 young patients with fractures of long bones. The parameters were measured first on admission and again after six to eight weeks. A group of healthy volunteers of similar age and sex served as control subjects. Plasma calcium level on the day of fracture was significantly reduced, 8.50 +/- 0.23 mg% (p less than 0.001). Serum CT level on the day of fracture was significantly increased, 0.18 +/- 0.02 ng/ml (p less than 0.05), and it continued to increase during the healing period, up to 0.23 +/- 0.02 ng/ml (p less than 0.001) after six to eight weeks. A significant rise was noted in plasma level of 24,25-(OH)2-D3, from 2.02 +/- 0.42 ng/ml on the day of fracture to 2.84 +/- 0.41 ng/ml six weeks later (p less than 0.05). No significant changes were found in serum PTH and plasma 25-(OH)-D3 levels on the day of fracture or during the healing process. The results suggest a possible physiologic active role for CT and 24,25-(OH)2-D3 in fracture healing in humans.