Responses to salmon calcitonin in chronic renal failure: relation to histological and biochemical indices of bone turnover.

Twenty-one patients with chronic renal failure and bone disease or hypercalcaemia were studied before and following single (twenty patients) or repeated (fourteen patients) intravenous injection of synthetic salmon calcitonin. Significant correlations were noted before treatment between bone surfaces occupied by osteoblasts or osteoclasts and plasma levels of immunoreactive parathyroid hormone, alkaline phosphatase and hydroxyproline. Following a single injection of 2--200 i.u. salmon calcitonin, plasma levels of calcium and phosphate fell for 6--8 h, but rose subsequently to pre-injection levels at 24 h. The magnitude and duration of the hypocalcaemic response was not clearly dose-dependent, but correlated with measured indices of bone cell activity. Repeated administration of calcitonin (10--200 i.u. thrice weekly for up to 2 months) lowered plasma calcium in the majority of patients and restored plasma calcium to normal in four previously hypercalcaemic patients. Mean levels of alkaline phosphatase increased but no significant changes in plasma phosphate, immunoreactive parathyroid hormone and calcitonin, or hydroxyproline occurred. Calcium absorption (six studies) did not change during treatment. We conclude that synthetic salmon calcitonin is an effective short-term inhibitor of bone resorption in patients with chronic renal failure. Its use as a possible treatment for hypercalcaemia and hyperparathyroid bone disease in chronic renal failure is discussed.