Skeletal Resistance to Parathyroid Hormone in Renal Failure

Abstract

The effects of an infusion of parathyroid extract on serum calcium and urinary phosphate levels were evaluated in 105 individuals—normal persons, patients with renal failure, patients treated with hemodialysis, and renal transplant recipients; patients were also studied after subtotal parathyroidectomy. The calcemic response was significantly lower than normal in all patients and was unrelated to the initial serum calcium, phosphorus, or immunoreactive parathyroid hormone levels. The calcemic response in advanced uremia varied inversely with preexisting bone resorption measured by microradiography. The parathyroid extract induced phosphaturia only in normal persons and those with mild-to-moderate renal failure. The results are consistent with skeletal resistance to the calcemic action of parathyroid hormone; this abnormality is seen early in the course of renal failure and is not reversed by hemodialysis. This derangement may contribute to the hypocalcemia of renal failure and hence play a role in the pathogenesis of secondary hyperparathyroidism in these patients.