Interleukin 1 enhances synovial cell hyaluronate synthesis.

Interleukin 1 enhances proliferation of murine thymocytes in the presence of lectins, and is also known to stimulate the release of prostaglandins and neutral proteases from a variety of cell types. We have previously shown that a factor isolated from the culture media of disaggregated lining cells of the human synovial membrane was indistinguishable from monocyte-derived interleukin 1. We report here that interleukin 1 from either source stimulates hyaluronate synthesis by synovial membrane cells. Upon gel filtration or isoelectric focusing of synovial cell supernatants, the hyaluronate-stimulatory activity co-fractionates with the interleukin 1 activity. Enhanced cell secretion of hyaluronate is a newly described metabolic effect of interleukin 1.