Synergism between parathyroid hormone and interleukin 1 in stimulating bone resorption in organ culture

Open Access
Publisher Website
Google Scholar
Abstract
The interaction of interleukin 1 (IL-1), a locally produced factor, and parathyroid hormone (PTH), a systemic factor, in stimulating bone resorption was examined using fetal rat long bone organ culture. Concentrations of IL-1 and PTH, which stimulated little bone resorption when present singly, produced marked resorption when present simultaneously. This synergistic interaction of IL-1 and PTH was not affected by the presence of the prostaglandin synthetase inhibitor indomethacin. Both interleukin 1α and interleukin 1β were capable of producing synergy. Synergy was not produced by sequential exposure of bone to IL-1 and PTH, but required the simultaneous presence of both mediators. The leftward shift in the dose response curve of PTH produced by IL-1 may be an important mechanism controlling localized bone resorption. A role for IL-1 in stimulating bone resorption in pathologic conditions, such as arthritis and periodontal disease, is strengthened by the finding that even low concentrations of IL-1 can produce resorptive effects by synergistic interaction with PTH.
Funding Information
  • Lucile Horton Howe and Mitchell B. Howe Foundation (DE-07378, DE-04881)
  • National Institute of Dental Research