Dioxins and endometriosis: a plausible hypothesis.

A potential connection exists between exposure to organochlorine chemicals and the increasing prevalence of endometriosis. Evidence shows that dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) can increase the incidence and severity of the disease in monkeys and can promote the growth or survival of endometrial tissue implanted into rodents in a surgically induced model of endometriosis. The mechanism of the connection between organochlorine chemicals and endometriosis is not clear. Effects on growth factors, cytokines, and hormones (components of the immune and endocrine systems) are potential means of mediating the possible promotion of endometriosis by dioxins. Studies on epidemiology and on structure-activity relationships of organochlorine chemicals and endometriosis have been additional approaches to this problem. In this regard, toxic equivalence (TEQ) appears to be an important determinant of the effects of organochlorine chemicals on endometriosis. In this article, we review the literature related to endometriosis and dioxins and attempt to integrate the various sources of information that bolster the hypothesis connecting dioxins and endometriosis.