Antiinflammatory and immunoregulatory effects of glucocorticoids: mode of action.

In this review emphasis is put on the mechanisms for the antiinflammatory and immunoregulatory role of glucocorticoids in man. Glucocorticoids have numerous effects some of which are permissive; steroids are thus important not only for what they do, but also for what they permit or enable other hormones and signal molecules to do. Some important effects are the result of altered protein synthesis due to steroidreceptor complex formation. One such protein is macrocortin which is induced by glucocorticoids. Macrocortin inhibits the enzyme phospholipase A2, thereby reducing the formation of prostaglandins and leukotriens. Steroids also reduce the release or synthesis of plasminogen activator and certain cytokines such as interleukin 1 and macrophage migration inhibitory factor. Glucocorticoids inhibit the release of histamin and lysosomal constituents of possible importance for the inflammatory response. In addition, steroids have profound effects on the circulation and distribution of white blood cells.