title: Synergism between parathyroid hormone and interleukin 1 in stimulating bone resorption in organ culture.
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 1 alpha and interleukin 1 beta 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.
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000187:drug effects*; D004357:Drug Synergism; D007213:Indomethacin / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D009924:Organ Culture Techniques; D010281:Parathyroid Hormone / Q000494:pharmacology*; D051381:Rats
chemical_list: D007375:Interleukin-1; D010281:Parathyroid Hormone; D007213:Indomethacin