Intermittently Administered Human Parathyroid Hormone(1–34) Treatment Increases Intracortical Bone Turnover and Porosity Without Reducing Bone Strength in the Humerus of Ovariectomized Cynomolgus Monkeys

• DOI: 10.1359/jbmr.2001.16.1.157
• Publication Date: 2006-04-27T03:05:53Z
• Authors: David B. Burr; Toru Hirano; Charles H. Turner; Charlotte Hotchkiss; Robert Brommage; Janet M. Hock
• Keywords: Bone remodeling

Cortical porosity in patients with hyperparathyroidism has raised the concern that intermittent parathyroid hormone (PTH) given to treat osteoporotic may weaken cortical bone by increasing its porosity. We hypothesized treatment of ovariectomized (OVX) cynomolgus monkeys for up 18 months recombinant human PTH(1-34) [hPTH(1-34)] LY333334 would significantly increase midshaft humerus but not have a significant effect on strength or stiffness humerus. also withdrawal PTH 6 after 12-month period return control OVX values. female were once daily subcutaneous (sc) injections hPTH(1-34) at 1.0 microg/kg (PTH1), 5.0 (PTH5), 0.1 ml/kg per day phosphate-buffered saline (OVX). Sham animals (sham) vehicle. After 12 months, was withdrawn from half each group (PTH1-W and PTH5-W), they treated remaining Double calcein labels before death months. death, static dynamic histomorphometric measurements made intracortically periosteal endocortical surfaces sections middiaphysis left Bone mechanical properties measured right humeral middiaphysis. dose dependently increased intracortical However, did detrimental bone. Most concentrated near surface where is small. In PTH5 monkeys, area (Ct.Ar) thickness (Ct.Th) because mineralizing surface. treatment, PTH1-W declined sham values, PTH5-W remained elevated compared sham. conclude intermittently administered increases dose-dependent manner does reduce