Connective Tissue Activation. XXI. Regulation of Glycosaminoglycan Metabolism by Lymphocyte (CTAP-I) and Platelet (CTAP-III) Growth Factors

The quantitative radiochemical methodology described in this report allows a major increase in information generation, increased experimental flexibility, improved statistical control, and increased diversity of information per culture. Other advantages relate to economies of technical time, supplies, cells, and test materials per individual culture. Microcultures of human synovial cells incorporate [14C]glucosamine into hyaluronic acid that accumulated primarily in the media and to a lesser extent in the cell mass. CTAP-I (from lymphoid cells), CTAP-III (from human platelets), PGE2, dibutyryl cAMP, and poly(I) . poly(C) markedly stimulated hyaluronate synthesis, whereas cortisol, cycloheximide, and tunicamycin inhibited stimulated synthesis. Time studies with cycloheximide indicated that translation, essential for the activation of synovial cells, was completed by 17 h postexposure to CTAP-I. Tunicamycin also seemed to inhibit CTAP-I induced activation primarily by interfering with translation; however, tunicamycin also caused modest post-translation inhibition of hyaluronate synthesis in activated adult human synovial cells.