Ionized calcium and the in vivo response of normal and hyperplastic parathyroid glands to beta-adrenergic agents.
We compared ionized serum calcium and parathyroid hormone (PTH) responses to the beta-adrenergic agents, isoproterenol and propranolol, in 14 patients with hyperparathyroidism following renal transplantation and 8 normal volunteers. Following isoproterenol, PTH rose in normal subjects concurrent with a significant (p less than 0.01) fall in ionized but not total, calcium. In the hyperparathyroid patients the PTH concentration decreased (p less than 0.001) coincident with a significant (p less than 0.01) increase in ionized, but not total, calcium. Changes in both PTH (p less than 0.05) and ionized calcium (p less than 0.05) were significantly different in hyperparathyroid patients compared to normal subjects. Propranolol did not affect PTH, ionized or total calcium in either group. We conclude that beta-adrenergic stimulation of PTH secretion may be mediated, in part, by antecedent changes in ionized calcium and not solely a direct effect of the agonist. Concurrent assessment of changes in ionized calcium is necessary for proper interpretation of investigations involving the sympathetic nervous system's regulation of PTH secretion.
D000328:Adult; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000502:physiology* / Q000503:physiopathology
D010281:Parathyroid Hormone; D011433:Propranolol; D007545:Isoproterenol; D002118:Calcium