Effect of cortisone and an anabolic steroid upon plasma hydroxyproline during fracture healing in rabbits

The effect of cortisone and an anabolic steroid on plasma hydroxyproline (HOP) was investigated in young male rabbits, following operative fracture of the radius. The action of these hormones was studied in three groups of animals, a cortisone (hydrocortisone sodium succinate 5mg/kg every day), an anabolic (norandronolone-19-phenylpropionate 5 mg/kg every other day) and a cortisone plus anabolic treated group. A fourth group of animals served as controls. Plasma HOP was found to increase during the fracture healing in control animals, particularly in the first week and during callus remodelling. Cortisone produced elevation of HOP level during the first two weeks followed by a decrease to low normal values. Animals treated with the anabolic did not present the initial rise but a sustained increase during callus remodelling. When both the anabolic and cortisone were administered, a curve similar to that of cortisone-treated animals was obtained. The initial increase of HOP is attributed to bone destruction and to a lesser degree to synchronous bone formation at the site of the fracture. This catabolic process seems to be enhanced by cortisone and inhibited by the anabolic. When, however, the two hormones are given together the protective anticatabolic effect of the anabolic is almost abolished.