Environmental Estrogens Stimulate Gene Transcription in the Prolactin Promoter

Abstract

The ability of environmental estrogens to regulate gene transcription on model and physiologically complex promoter
was examined in GH3 cells, a pituitary cell line. In transient transfection studies, the pGL3 model promoter and the
physiologically complex prolactin promoter were both responsive to the xenoestrogen bisphenol A and the
phytoestrogen daidzein in a dose related manner. These transcriptional responses were mediated by estrogen receptors,
as responses were ameliorated in the presence of ICI 180, 782, a pure antiestrogen. Cotransfection of Pit-1 significantly
enhanced the transcriptional response of the prolactin promoter to stimulation by environmental estrogens. The nature
and magnitude of transcriptional responses to estradiol sensitive genes following challenge by environmental estrogens
is likely dependent on regulatory elements found in the promoter and their ability to recruit transcription factors.