We evaluated the acute response of parathyroid hormone (PTH) and calcitonin (CT) secretion to non-selective and beta-1 selective antagonists and studied the long -term effects of non-selective betaantagonists on calcium metabolism in chronic hemodialysis patients . Administration of exprenolol (non-selective) and metoprolol (beta-1 selective) depressed thePTH secretion similarly . Long-term administration of non-selective beta-antagonists resulted in a significant decrease in PTH , CT and alk

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... ine phosphatase levels without producing any changes in calcium and phosphate levels . Th ese results suggest that 1) beta-1 adrenergic receptors may play an imp ortant role in the regulation of PTH secretion, 2) the beta-adrenergic system may also play a role in the regulation of CT secretion, and 3) beta-antagonist therapy may be useful for the prevention of secondary hyperparathyroidism in chronic hemodialysis patients.