Connective tissue activation. XX. Stimulation of prostaglandin secretion by mediators from lymphocytes (CTAP-I) and platelets (CTAP-III).

Connective tissue activating peptides from lymphocytes (CTAP-I) and platelets (CTAP-111) are known to stimulate glycosaminoglycan synthesis, glycolysis, and mitogenesis in connective tissue cell cultures. Direct evidence suggested that increased accumulation of cyclic AMP was involved in the action of these peptide agonists, and increased prostaglandin E synthesis was postulated on the basis of indirect evidence. In the present experiments, CTAP-I and -111 were incubated with human and murine cells in culture, and prostaglandin E was measured by radioimmunoassay using antibody directed primarily to prostaglandin E2. Both CTAP-I and -111 markedly stimulated the elaboration of prostaglandin E into culture medium, the earliest evidence of increased synthesis occurring at 4 hours with maximal concentrations found at 24 hours. Substantial residual stimulation persisted at least through 48 hours. Indomethacin (13.0 pg/ml) obliterated basal and incremental synthesis of prostaglandin in the presence of mediators.