Effect of porcine calcitonin therapy on vitamin D metabolism and clinical response in a patient with osteogenesis imperfecta.

A 1 11/12-year-old girl with osteogenesis imperfecta was treated with porcine calcitonin. Eight bone fractures occurred in the previous 20 months before therapy, but none occurred during eight months of therapy. There was also a significant improvement in linear growth and radiographic bone density. This is the first study of the effect of calcitonin on vitamin D metabolism in a human. The high plasma levels of 1,25 dihydroxy-vitamin D (1,25-(OH)2-D) and 24,25 dihydroxy-vitamin D (24,25-(OH)2-D) before calcitonin therapy decreased after therapy. Plasma 25 hydroxy-vitamin D (25-OH-D) concentration, which normal in level before calcitonin therapy, was normal or slightly decreased during administration. It is concluded that calcitonin probably influences vitamin D metabolism in a patient with osteogenesis imperfecta.