A new screen for anti-inflammatory agents. Estimation of rat serum acute phase alpha2-macroglobulin levels using an electroimmunoassay.

Induction of alpha2-macroglobulin acute phase protein in rats by the injection of turpentine revealed strain and sex differences in the amounts of this protein detected in sera by rocket immunoelectrophoresis. Studies in vivo with a wide variety of drugs showed that non-steroidal anti-inflammatory drugs (NSAID) such as aspirin, indomethacin and BW 755C as well as colchicine, clofibrate and clozic, inhibited serum concentrations of the acute phase protein 48 h after turpentine injection. The procedure used offers a new and convenient screen for assessing NSAIDs and the method may be of value as a screen for new clozic-like compounds with anti-rheumatic activity. The possibility that the NSAIDs are inhibiting a humoral factor initiated by the inflammatory stimulus and that the humoral factor is a metabolite of arachidonic acid is discussed.