Nitric oxide and bone

摘要: Nitric oxide (NO), a mediator of cardiovascular homeostasis, neurotransmission, and immune function, has recently been found to have important effects in bone. Both constitutive inducible forms NO synthase are expressed by bone-derived cells, cytokines such as interleukin-1 (IL-1), tumor necrosis factor (TNF), interferon gamma (IFN-gamma), potent stimulators production. When combined with other cytokines, IFN-gamma markedly induces production, which suppresses osteoclast formation activity mature osteoclasts. This "superinduction" is largely responsible for the selective inhibitory effect on cytokine-induced bone resorption. High concentrations also cells osteoblast lineage, production appears be partly proliferation. At lower concentrations, however, different effects. Moderate induction potentiates resorption, at low promotes proliferation osteoblast-like modulates function. therefore an regulatory molecule lineage represents one molecules produced osteoblasts directly regulate osteoclastic activity. Stimulation proinflammatory raises possibility that may involved disease conditions associated cytokine activation, rheumatoid arthritis, osteolysis, postmenopausal osteoporosis.