The NIEHS researchers treated normal female mice and female mice that lack estrogen receptor beta with fertility drugs similar to those commonly used by women undergoing fertility treatments. The mice lacking this receptor are more likely to exhibit infertility or subfertility, including producing fewer offspring, or having less frequent pregnancies. Treatment with fertility drugs did not improve ovulation rates in these studies.
Years of study have shown that the hormone estrogen plays an important role in a variety of systems, most especially female reproduction. However, it was generally thought that there was only one receptor, the alpha receptor, that responded to estrogen. It wasn’t until 1996 that the second receptor, estrogen receptor beta, was discovered. The current study provides evidence that the beta receptor plays a more significant role in ovarian function than the alpha receptor. Researchers would like to further their investigation into the role of the beta receptor by studying women already undergoing fertility treatment.
“The tools and animal models necessary to do these types of studies have only recently become available, but are already helping us to better understand the role of estrogen in the ovary,?said John Couse, Ph.D., lead author of the August paper.
An earlier NIEHS study published in the June issue of Endocrinology, used a test tube or in vitro approach, to elucidate the role that estrogen receptors play in ovulation. “The combination of the two different methods, the in vivo and in vitro studies, complement each other nicely and provide more precise answers to the role that the estrogen receptor beta plays in ovulation,?said lead author Judith Emmen, Ph.D.
The estrogen receptor beta is also known to respond to environmental and dietary chemicals that can mimic the effects of estrogen and stimulate the body’s natural hormones. One example is genistein, a common com