title: Rapid suppression of S-PTH by oral calcitriol and calcium in healthy premenopausal women.
abstract: The influence of oral calcium +/- cholecalciferol or calcitriol on S-PTH and whole blood ionized calcium (B-Ca++) in the very short term has not been elucidated. B-Ca++ and S-PTH were measured after overnight fast every 5 or 15 min for 4-h in 7 healthy premenopausal women (30-45 years) in a crossover design where the subjects were studied on 4 different days. Study 1: (control), 125-ml tap water (also given in studies 2-4); study 2: 1000 mg calcium, as calcium carbonate; study 3: 1000 mg calcium and 400 IU (5 microg) cholecalciferol; and study 4: 0.5 microg calcitriol plus 1000 mg calcium. Calcium plus 1,25(OH)2 vitamin D3 induced a rapid and significant fall in S-PTH compared to the control period (p < 0.02). Calcium alone or calcium plus cholecalciferol did not change the PTH levels significantly compared to control (water). B-Ca++ increased significantly after calcium plus 1,25(OH)2 vitamin D3 (p<0.01) and calcium plus cholecalciferol (p<0.05) compared to the control period. The B-Ca++ elevation was significantly higher after calcium plus 1,25 vitamin D3 than after calcium plus cholecalciferol (p<0.05). In conclusion, oral calcitriol plus calcium causes a rapid elevation in B-Ca++ and suppression of the PTH secretion also in the short term (hours).
authors.affiliation: Department of Endocrinology PE, Rigshospitalet, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Tfelt-Hansen
authors.forename: P
authors.initials: P
authors.lastname: Schwarz
authors.forename: O
authors.initials: O
authors.lastname: Torring
mesh_terms: D000328:Adult; D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology*; D002118:Calcium / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002119:Calcium Carbonate / Q000008:administration & dosage / Q000494:pharmacology; D002762:Cholecalciferol / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D006801:Humans; D007700:Kinetics; D010281:Parathyroid Hormone / Q000097:blood*; D010710:Phosphates / Q000652:urine; D017697:Premenopause
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates; D002762:Cholecalciferol; D002117:Calcitriol; D002119:Calcium Carbonate; D002118:Calcium