Hormonal control of fracture healing in a dog with chorea.

An experimental fracture in a dog with chorea was found to heal faster, and with a larger callus, than normal. Serum levels of parathormone (PTH), calcitonin (CT) and vitamin D metabolities were determined during callus formation. Serum concentrations of vitamin D metabolites were lower from the beginning while serum CT levels were higher compared to normal dogs. A massive increase in serum levels of 24,25-dihydroxyvitamin D was noted during the healing period. These results and observations suggest the existence of some disturbances in the secretion of hormones regulating calcium metabolism during bone repair where a nervous system lesion exists.