Evidence that intermittent treatment with parathyroid hormone increases bone formation in adult rats by activation of bone lining cells.

• DOI: 10.1210/endo.136.8.7628403
• Publication Date: 2014-01-08T16:07:19Z
• Authors: H Dobnig; R T Turner
• Keywords: Osteoid; Osteopontin; Metaphysis; Epiphysis

Previous studies demonstrated that intermittent treatment with PTH increases osteoblast number and bone formation in growing adult rats. The cellular mechanism for this increase was investigated 16-month-old female Continuous [3H]thymidine infusion over a 1-week [human PTH-(1-34)] period performed to determine the percentage of newly formed osteoblasts originate from progenitor cells. To verify formation, we histomorphometry Northern blot analysis selected matrix proteins. resulted dramatic fluorochrome-labeled perimeter (727%), osteoid (735%), (626%), steady state mRNA levels osteocalcin (946%) type 1 collagen (> 1000%). Autoradiographic metaphyseal sections revealed no difference [3H]thymidine-labeled between PTH- vehicle-treated groups (4.3 +/- 1.3% vs. 5.7 2.7%, respectively). Similar changes were observed PTH-treated ovariectomized As PTH-induced did not require proliferation cells carried out an additional experiment rats onset action. Incorporation [3H]proline distal femoral epiphysis increased within 24 h. We conclude rapid rise cell most likely due activation preexisting lining osteoblasts.