title: Marked reduction of bone turnover by alendronate attenuates the acute response of bone resorption marker to endogenous parathyroid hormone.
abstract: The aim of this study was to assess the effects of the antiresorptive treatments of alendronate (ALN), risedronate (RIS) and raloxifene (RLX) on the response of bone to endogenous parathyroid hormone (PTH) induced by acute hypocalcemia. Forty women (age, 55-80 years) with postmenopausal osteoporosis (treated with ALN, RIS and RLX or untreated-control group) were given infusions of sodium ethylenediaminetetraacetic acid (EDTA; 10 mg/kg of body weight). Serum ionized calcium (iCa), plasma intact PTH and marker of bone resorption, serum beta C-terminal telopeptide of type I collagen (beta-CTX; beta CrossLaps) were followed for 180 min. In all women, decrease in serum iCa following the EDTA load resulted in an acute increase in serum PTH. Between 60 and 180 min, plasma PTH in the ALN and RIS treated women remained significantly higher than in the control group. The integrated beta-CTX responses (area under curves, AUCs) to peaks of PTH were significantly lower in the ALN treated women than in those treated with RIS, RLX or control group. There was no significant difference in beta-CTX AUC response to PTH between RIS, RLX and control women. Taken together, these findings suggest that in women with postmenopausal osteoporosis treated with ALN, a substantial reduction of bone turnover blunts the acute bone resorbing effect of endogenous PTH.
authors.affiliation: Department of Internal Medicine 3, Charles University, Faculty of Medicine, Prague, Czech Republic.
authors.forename: Vit
authors.initials: V
authors.lastname: Zikan
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Stepan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019386:Alendronate / Q000627:therapeutic use*; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D016723:Bone Remodeling / Q000187:drug effects*; D001862:Bone Resorption / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D024042:Collagen Type I / Q000187:drug effects; D004492:Edetic Acid / Q000494:pharmacology; D012968:Etidronic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000139:chemically induced; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000188:drug therapy*; D010281:Parathyroid Hormone / Q000378:metabolism*; D010455:Peptides / Q000187:drug effects; D020849:Raloxifene Hydrochloride / Q000627:therapeutic use; D000068296:Risedronic Acid
chemical_list: D015415:Biomarkers; D050071:Bone Density Conservation Agents; D002614:Chelating Agents; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D020849:Raloxifene Hydrochloride; D004492:Edetic Acid; D000068296:Risedronic Acid; D012968:Etidronic Acid; D019386:Alendronate