Presence of immunoreactive endothelin in synovial fluid: analysis of 22 cases.

The concentration of endothelin in inflammatory and noninflammatory synovial fluids (SF) was measured by a sensitive radioimmunoassay. Endothelin-like immunoreactivity was detectable in all SF samples and the mean concentration of endothelin was 2.6±0.3 pg/ml, more than twice that in normal human plasma