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Patients with steroid-induced, juvenile and senile osteoporosis were studied using balance techniques. The changes in calciun and phosphorus balance associated with glucocorticoid therapy were corrected with vitamin D and bendrofluazide given in combination. No hypercalcaemia occurred in osteoporotic patients who continued to receive glucocorticoids. Calcium and phosphorus balance was also improved in the osteoporotic subjects not receiving steroids, but these patients became hypercalcaemic during treatment. It is suggested that vitamin D, bendrofluazide and steroids antagonize the actions of one another on the renal tubule, gut and bone and in this way prevent the increased calciuria which occurs with glucocorticoid therapy. Since the increased calciuria and negative calcium balance induced by glucocorticoids is considered to be the result of excessive bone resorption, an adequate dose of bendrofluazide and vitamin D in combination might prevent the development of, or even reverse, steroid-induced osteoporosis.

We report data from three patients with severe Paget's disease of bone who were treated with mithramycin.Mithramycin infusion resulted in a fall in plasma calcium, phosphate, alkaline phosphatase, and urinary hydroxyproline excretion. There was an improvement in calcium and phosphorus balance in two of the three subjects studied. A pronounced or complete relief of bone pain occurred in all three.We suggest that mithramycin exerts its beneficial effect in Paget's disease of bone by stimulating parathyroid hormone release. The parathyroid hormone released has a predominantly anabolic action on bone since its catabolic action is blocked by mithramycin, which inhibits bone resorption.

With an oral phosphate tolerance test a primary defect in intestinal phosphate absorption was found in patients with untreated familial and non-familial hypophosphataemia. It is suggested that this plays a major part in the aetiology of rickets and osteomalacia in these disorders. Vitamin D was shown to have a beneficial effect on intestinal transport of phosphate, though defective absorption was not completely corrected. If intestinal phosphate absorption is normal, oral phosphate supplements will maintain normal plasma phosphate levels even in the presence of a pronounced renal phosphate leak.In familial and non-familial hypophosphataemia the phosphate tolerance test may be a more sensitive index of genetic abnormality than a low plasma phosphate. It may be helpful in distinguishing several syndromes at present classified under non-familial hypophosphataemia, as well as assessing the response to treatment with vitamin D and in investigating intestinal transport of phosphate.