Estrogen Associated Gene Imprinting and Developmental Diseases

John McLachlan
Center for Bioenvironmental Research; Tulane and Xavier Universities

Many chemicals have estrogenic activity. Exposure to estrogens during critical periods of cellular differentiation is associated with long-term defects in the function of the reproductive system. In some cases these functional defects, including cancer, may persist for more than one generation. We have shown that developmental exposure to the synthetic estrogen, diethylstilbestrol (DES), results in rare forms of neoplasia that are transmitted to the second generation. Developmental treatment with estrogenic compounds can be shown to persistently alter expression of estrogen responsive genes. Some of these altered genes also show alterations in the methylation pattern of their promoters. Our work suggests that epigenetic imprints may be a feature of estrogen action during developmental programming of cells. Work from other laboratories suggests an expansion of this concept of developmental epigenetic imprinting to other hormonally active environmental chemicals.