Danazol. A synthetic steroid with diverse biologic effects

Danocrine (danazol) is a synthetic steroid with multiple and diverse biologic effects. It exerts these effects by binding to steroid transport proteins in the circulation and to specific receptors in target tissues. Centrally, danazol inhibits gonadotropins, suppressing gametogenesis and steroidogenesis. Gonadal and adrenal steroidogenesis are suppressed further through danazol's direct effect on specific enzyme systems. Danazol also displays immunoregulatory effects both in vivo and in vitro. In endometriosis, danazol induces amenorrhea and a hypoestrogenic state, resulting in endometrial atrophy. The drug's direct binding to androgen and progesterone receptors in endometriotic tissue may contribute further to the suppression of endometriosis. In women with endometriosis who produce autoantibodies against endometrial cells and endometrial cell-derived phospholipids, histones and nucleotides, danazol may improve reproductive performance through the suppression of abnormal autoantibody levels. In several other autoimmune and genetic disorders danazol brings about a clinical improvement by lowering abnormal autoantibody production or by increasing the concentration of genetically deficient protein. In order to explore the full clinical potential of the drug and to better understand danazol's mechanism of action and especially its immunoregulatory effects in autoimmune diseases and endometriosis, further investigation is necessary.