THE SYNOVIAL PRODUCTION OF COLLAGENASE AND CHONDROCYTE ACTIVATING FACTORS IN RESPONSE TO COBALT

Addition of CoCl//2 solutions to the culture media of confluent monolayers of lapine or human synoviocytes stimulated their production of the neutral proteinases collagenase, gelatinase, and caseinase. With lapine cells, maximum stimulation occurred at 10** minus **7 M CoCl//2, while human cells required 10** minus **4-10** minus **5 M CoCl//2 to achieve a maximum stimulation. Production of prostaglandin E//2 by lapine cells was enhanced some 30-40% by concentrations of CoCl//2. Lapine synovial cells that had been stimulated by CoCl//2 also produced a substance, or substances, that provoked the synthesis of collagenase, gelatinase, caseinase, and prostaglandin E//2 by monolayers of articular chondrocytes. Chondrocytes themselves, however, resisted activation by CoCl//2.