July 20, 2005

Estrogen gene helps explain some infertility-study

WASHINGTON (Reuters) - Fertility drugs may not help certain
women if they lack a certain estrogen-related gene, scientists
studying mice suggested on Wednesday.

Mice genetically engineered to lack the gene did not
ovulate in response to fertility drugs, the researchers found.

If the same is true in women, it could help explain some
forms of infertility and also help steer women away from
treatments unlikely to help them.

The gene is called estrogen reseptor beta, the team of
National Institutes of Health researchers report in the August
issue of Endocrinology.

"What we found is that the beta estrogen receptor plays a
role in moving the egg outside the ovary so it can be
fertilized," Kenneth Korach of the National Institute of
Environmental Health Sciences (NIEHS) said in a statement.

"We never knew before what function this receptor played in

The NIEHS researchers treated normal female mice and
genetically engineered mice with fertility drugs similar to
those commonly used by women undergoing fertility treatments.

The mice bred to lack this receptor gene were more likely
to be infertile, or had fewer offspring. When treated with
fertility drugs the mice did not produce more egg cells.

"Dealing with infertility can be emotionally, financially,
and physically draining," said Dr. David Schwartz, director of
the NIEHS.

"If we can help couples understand the reasons for their
infertility, doctors can further define their treatment
options, help them to minimize the expense and risk of taking
drugs that may be less effective for them, and increase their
chances of having a ... healthy child."

The NIEHS may also try to find out whether defects in
estrogen receptor beta are inherited or caused by some
environmental effect -- and whether perhaps diet can alter the

Estrogen receptor beta is known to respond to environmental
and dietary chemicals that can mimic the effects of estrogen
and stimulate the body's natural hormones, such as genistein, a
compound found in soy products, the NIEHS said.