The anabolic effects of parathyroid hormone on cortical bone mass, dimensions and strength--assessed in a sexually mature, ovariectomized rat model.
The aim of the study was to determine the effect of parathyroid hormone (PTH), the antiresorptive agents estrogen and bisphosphonate (risedronate), and also the combination of PTH with these antiresorptive drugs on femoral cortical bone mass, dimensions and strength in a sexually mature, ovariectomized rat model. A total of 138, 3-month-old Sprague-Dawley rats were randomized into seven groups: 1--sham operated (control); 2--ovariectomized (OVX); 3--OVX plus estrogen; 4--OVX plus bisphosphonate (risedronate [NE]; 5--OVX plus hPTH (1-34); 6--OVX plus hPTH (1-34) and estrogen; 7--OVX plus hPTH (1-34) and risedronate. Treatment regimens were initiated 4 weeks after OVX and were continued for 5 and 15 weeks for each treatment group. Changes in bone mass (ash content), cross-sectional area, cortical thickness and dimensions and bone strength were assessed in middiaphyseal, femoral specimens. The results revealed that ovariectomy had no effect on cortical bone mass and biomechanical competence. OVX rats treated with estrogen and also OVX rats treated with risedronate showed no significant difference from either OVX or control groups. After only 5 weeks of treatment, hPTH monotherapy increased ash content, cross-sectional area, cortical thickness and compressive bone strength (load) significantly. After 15 weeks of treatment, OVX rats treated with PTH monotherapy or PTH in combination with risedronate showed identical load-values. These values were significantly higher than those seen in both control and OVX rats. However, PTH in combination with estrogen failed to augment cortical bone strength over control or OVX levels after therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
Mosekilde
L
L
Department of Connective Tissue Biology, University of Aarhus, Denmark.
Danielsen
C C
CC
Søgaard
C H
CH
McOsker
J E
JE
Wronski
T J
TJ
D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects*; D001851:Bone Diseases, Metabolic / Q000188:drug therapy / Q000209:etiology; D016723:Bone Remodeling / Q000187:drug effects; D001862:Bone Resorption / Q000188:drug therapy; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology; D004195:Disease Models, Animal; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D012968:Etidronic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D005269:Femur / Q000187:drug effects / Q000473:pathology; D010052:Ovariectomy; D010281:Parathyroid Hormone / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D000068296:Risedronic Acid; D019379:Teriparatide
D002121:Calcium Channel Blockers; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D019379:Teriparatide; D004958:Estradiol; D000068296:Risedronic Acid; D012968:Etidronic Acid