BPA exposure in pregnant mice changes gene expression of female offspring
2012-06-27
(Press-News.org) Prenatal exposure to bisphenol A, or BPA, a chemical found in many common plastic household items, can cause numerous genes in the uterus to respond differently to estrogen in adulthood, according to a study using a mouse model. The results will be presented Tuesday at The Endocrine Society's 94th Annual Meeting in Houston.
The study, led by Hugh Taylor, MD, professor and chief of the reproductive endocrinology section at Yale University School of Medicine, observed "major and permanent changes in gene expression" in female mice exposed to BPA as a fetus. Taylor said these differences were apparent only after estrogen exposure, either naturally at puberty or with estrogen treatment.
"Hyperresponsiveness to estrogens is a potential mechanism to explain the increased incidence of estrogen-related disorders seen after exposure to endocrine disrupters like BPA," Taylor said.
BPA has estrogen-like properties and has been linked to breast cancer and many female reproductive disorders that are sensitive to estrogen. These problems include uterine fibroids (benign tumors), endometriosis and endometrial hyperplasia, an abnormal thickening of the lining of the uterus that can lead to uterine cancer.
Taylor and his co-workers gave pregnant mice either BPA or an inactive substance for about two weeks beginning on the ninth day of pregnancy. After the mice gave birth, the scientists removed and tested the uterus of half of the female offspring before sexual maturation, looking for changes in gene expression. The other half of the female offspring had removal of their ovaries at 6 weeks of age, followed by treatment with estradiol, an estrogen. They then underwent uterine removal and testing after puberty at 8 weeks of age.
Before sexual maturation, gene expression was "remarkably similar" among control mice—those that were not exposed to BPA in the womb—and the mice that were prenatally exposed to BPA, Taylor said. Of 45,000 genes screened, only 18 showed twofold or greater changes in expression, the authors reported.
After estrogen exposure at puberty, the gene expression profile had changed greatly in BPA-exposed offspring, with 365 genes showing altered expression, according to the study abstract. Of these genes, 208 also showed aberrations in the usual pattern of DNA methylation, a biochemical process that regulates gene expression. At least 14 of the 208 genes have known estrogen response elements, areas that indicate that they are directly regulated by estrogen through its receptor.
Among the BPA-exposed mice, another 316 genes showed altered response to estradiol at puberty. This included several genes that have not previously demonstrated an exaggerated response to estradiol treatment or genes that have not been known to be regulated by estrogen, Taylor said.
"BPA exposure in utero appears to program uterine estrogen responsiveness in adulthood," he said. "Pregnant women should minimize BPA exposure."
INFORMATION: END
ELSE PRESS RELEASES FROM THIS DATE:
2012-06-27
Obese children show greater exposure than nonobese children to a phthalate, a chemical used to soften plastics in some children's toys and many household products, according to a new study, which found that the obesity risk increases according to the level of the chemical found in the bloodstream. The study will be presented Saturday at The Endocrine Society's 94th Annual Meeting in Houston.
The chemical, di-ethylhexyl phthalate (DEHP), is a common type of phthalate, a group of industrial chemicals that are suspected endocrine disruptors, or hormone-altering agents.
In ...
2012-06-27
Prenatal exposure to the environmental contaminants polychlorinated biphenyls, or PCBs, causes long-term changes to the developing brain that have adverse effects on reproductive function later in life, a new study finds. Results will be presented Saturday at The Endocrine Society's 94th Annual Meeting in Houston.
The study used rats, whose genes and molecules in the hypothalamus—the region of the brain important for reproductive function—are virtually identical to those in humans, according to co-author Andrea Gore, PhD, professor of pharmacology and toxicology at the ...
2012-06-27
A large study in people at risk of diabetes has found a direct association between the presence of a small genetic alteration in a hormone receptor and increased body fat and insulin resistance. The results, to be presented Tuesday at The Endocrine Society's 94th Annual Meeting in Houston, suggest an adverse role for a previously described genetic variant, the BclI polymorphism.
"Our findings support the idea that even small variations in hormone receptor sensitivity can have metabolic implications, such as obesity or diabetes," said co-author Bastiaan Havekes, MD, PhD, ...
2012-06-27
A picture may be worth a thousand calories, a new study suggests. Looking at images of high-calorie foods stimulates the brain's appetite control center and results in an increased desire for food, according to the study, which will be presented Monday at The Endocrine Society's 94th Annual Meeting in Houston.
"This stimulation of the brain's reward areas may contribute to overeating and obesity," said the study's senior author, Kathleen Page, MD, assistant professor at the University of Southern California, Los Angeles.
"We thought this was a striking finding, because ...
2012-06-27
Calcium and vitamin D supplements are associated with high calcium levels in the blood and urine, which could increase the risk of kidney stones, a new study finds. The results will be presented Tuesday at The Endocrine Society's 94th Annual Meeting in Houston.
"The use of calcium and vitamin D supplementation may not be as benign as previously thought," said principal investigator J. Christopher Gallagher, M.D., professor and director of the Bone Metabolism Unit at Creighton University Medical Center in Omaha, NE. "Pending further information, people should not exceed ...
2012-06-27
Women with polycystic ovary syndrome (PCOS) who also have obstructive sleep apnea have at least three times the risk of having prediabetes compared with women who do not have PCOS, according to a new study. The results will be presented Tuesday at The Endocrine Society's 94th Annual Meeting in Houston.
"In the last few years, sleep apnea has been found to be a frequent comorbidity [coexisting condition] with PCOS, and our study shows that women who have both conditions are at greatest risk of metabolic disturbances such as prediabetes," said the study's senior author, ...
2012-06-27
A more accurate, faster diagnostic test for Group B Streptococcal infection in babies has been reported in the Journal of Medical Microbiology. The new test could allow better treatment and management of the disease and reduce the risk of mortality among newborns.
Group B streptococcus (GBS) infections, caused by the bacterium Streptococcus agalactiae, are the most common cause of meningitis, septicaemia and pneumonia in newborns. In 2010 there were 506 cases of GBS infections in infants across England, Wales and Northern Ireland.
Health Protection Agency (HPA) researchers ...
2012-06-27
A rare kind of mineral which scientists hope could be used to remove toxic metals and radioactive species from the environment played a similar, crucial role early in Earth's history.
Research carried out by an international team of leading biogeochemists suggests for the first time that 'green rust' was likely widespread in ancient oceans and may have played a vital role in the creation of our early atmosphere.
Led by Newcastle University, UK, the study shows that during the Precambrian period, green rust 'scavenged' heavy metals such as nickel out of the water. Nickel ...
2012-06-27
Women who have a fear of childbirth spend longer in labour than women who have no such fear, suggests new research published today (27 June) in BJOG: An International Journal of Obstetrics and Gynaecology.
Between 5 and 20% of pregnant women have a fear of childbirth. Various factors have been associated with increased prevalence of fear of childbirth, including young maternal age, being a first-time mother, pre-existing psychological problems, lack of social support and a history of abuse or adverse obstetric events.
This Norwegian study looked at 2206 women with ...
2012-06-27
Women who regularly eat a low carbohydrate, high protein diet are at greater risk of cardiovascular disease (such as heart disease and stroke) than those who do not, a study published on bmj.com today suggests.
Although the actual numbers are small (an extra 4-5 cases of cardiovascular disease per 10,000 women per year) the authors say that this is a 28% increase in the number of cases and that these results are worrying in a population of young women who may be exposed to these dietary patterns and face the excess risk for many years.
Low carbohydrate-high protein ...
LAST 30 PRESS RELEASES:
[Press-News.org] BPA exposure in pregnant mice changes gene expression of female offspring