Effects of prednisone and deflazacort on mineral metabolism and parathyroid hormone activity in humans.

The effects of two different glucocorticoids, prednisone and deflazacort, (an oxazoline derivative of prednisolone) on bone metabolism were analyzed in 10 patients with disorders that required glucocorticoid therapy. Significant elevations in blood immunoreactive parathyroid hormone, alkaline phosphatase and urinary calcium, phosphate, hydroxyproline and nephrogenous cyclic AMP were observed during prednisone therapy in addition to an increase in the exchangeable calcium pool as estimated by 47Ca-kinetic analyses. In contrast to these changes, deflazacort therapy induced minimal, and in some instances, no changes in these indices. In fact, in studies wherein prednisone therapy was followed by deflazacort alterations in bone metabolism, iPTH, and nephrogenous cAMP observed during prednisone were reversed. The data are consistent with the fact that the skeletal effects of prednisone therapy are mediated, at least in part, by increased parathyroid hormone activity, and that deflazacort is less potent in this regard.