Australia - Do Female Hormones Contribute To Obesity?

Scientists suggest that exposure to estrogen from soy products or PVC plastics could explain the higher rates of obesity in males of developed countries.

AsianScientist (Jun 16, 2014) – An imbalance of female sex hormones among men in Western nations may be contributing to high levels of male obesity, according to new research from the University of Adelaide.

In a paper published in the journal PLOS ONE, researchers from the University’s School of Medical Sciences suggest that obesity among Western men could be linked with exposure to substances containing the female sex hormone estrogen – substances that are more often found in affluent societies, such as soy products and plastics.

Mr. James Grantham, medical student at the university, compared obesity rates among men and women from around the world with measures such as gross domestic product to determine the impact of affluence on obesity. He found that while it was normal for women in the developing world to have significantly greater levels of obesity than men, the developed world offers quite a different picture.

“Hormonally driven weight gain occurs more significantly in females than in males, and this is very clear when we look at the rates of obesity in the developing world,” Grantham said.

“However, in the Western world, such as in the United States, Europe and Australia, the rates of obesity between men and women are much closer. In some Western nations, male obesity is greater than female obesity.

While poor diet is no doubt to blame, this research strongly suggests that there might be more to the obesity epidemic than just high caloric intake.

Professor Maciej Henneberg, co-author of the study, said, “Exposure to estrogen is known to cause weight gain, primarily through thyroid inhibition and modulation of the hypothalamus. Soy products contain xenoestrogens, and we are concerned that in societies with a high dietary saturation of soy, such as the United States, this could be working to ‘feminise’ the males. This would allow men in those communities to artificially imitate the female pattern of weight gain.

“Another well-established source of xenoestrogen is polyvinyl chloride, known as PVC. This product is in prominent use in most wealthy countries, from plastic medical devices to piping for our water supplies.”

Micro-evolutionary changes may be occurring within Western societies that could also be leading to changes in testosterone and estrogen in men.

“This would certainly explain the various concerns about sperm count reductions among men in developed nations,” Henneberg said.

The authors said further research is needed to better understand whether or not environmental factors are leading to a “feminisation” of men in the Western world.

Health & Medicine

The article can be found at: Grantham and Henneberg. (2014) The Estrogen Hypothesis of Obesity.

Source: University of Adelaide; Photo: Tony Alter/Flickr/CC.

Australia - Hormones Can Change DNA In Breast Cells, Study

Scientists in Australia have discovered how female steroid hormones can make dramatic changes to the genetic material in breast cells.

Scientists in Australia have discovered how female steroid hormones can make dramatic changes to the genetic material in breast cells, changes that could potentially lead to breast cancer.

The study, published recently in the journal Cell Reports, was conducted by researchers from the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia.

Here, they created a roadmap of the epigenomes of different breast cell types, and determined how the epigenomes changed in response to ovarian hormones such as progesterone. The epigenome is a series of chemical tags that modify DNA, controlling which genes are switched on and off.

“We found the epigenome was very sensitive to hormonal regulation,” said Professor Jane Visvader, a senior author on the study. “This reveals another way in which female hormones can influence breast cancer risk – by altering the epigenome through modifications in DNA tags.”

The epigenome is where the DNA and the environment intersect, communicating signals from the outside world to the DNA. The epigenome doesn’t alter the genetic code, but is a layer of proteins that sits ‘on top’ of the DNA and provides instructions on whether DNA should be read and ‘switched on’ to produce proteins.

The research team found that pregnancy hormones activate a molecule called EZH2, which is an important modifier of the epigenome.

“We found that hormones including progesterone activate EZH2 to modify the epigenome, leading to global changes in the expression of a huge number of genes,” Visvader said.

“In normal tissue, EZH2 is essential for the development of breast tissue including ducts and milk-producing cells, and for maintaining the activity of breast stem cells and their daughter progenitor cells.

However, life-long exposure to hormones could lead to breast tumor initiation through increased levels of EZH2 and the changes that it orchestrates in the epigenome,” she explained.

Breast cancer is the most common cause of cancer in women, accounting for almost 30 percent of all cancers affecting women. High levels of EZH2 are a marker of poor prognosis in breast cancer and have been frequently observed in basal-like breast cancers, the most aggressive types of breast cancer.

“The link between progesterone, EZH2 and the epigenome, could be crucially important in the very early stages of breast cancer development,” she said.

Professor Geoff Lindeman, another senior author on the study, said there were decades of evidence linking hormone exposure with breast cancer, but the hormones’ influence on the epigenome was not known.

“Our discovery points to a role for hormone-induced changes in the epigenome in the early stages of breast cancer initiation, and could lead to new therapeutics for treating breast cancer,” Lindeman said.

“Inhibitors against EZH2 are being developed by others, but it will be several years before we know the outcome of these on cancer.”

The article can be found at: Pal B et al. (2013) Global Changes in the Mammary Epigenome Are Induced by Hormonal Cues and Coordinated by Ezh2.

Source: WEHI;

Health & Medicine

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Australia - Scientists Find New Ways To Detect Cell Receptor Cross-Talk

Innovative new technology has been used to identify and profile a novel combination of proteins that may improve treatment for prostate disorders.

Innovative new technology has been used to identify and profile a novel combination of proteins that may improve treatment for prostate disorders.

Researchers from the Western Australian Institute for Medical Research (WAIMR) and The University of Western Australia (UWA), in collaboration with the Monash Institute of Pharmaceutical Sciences in Melbourne, have found novel ways to identify G protein-coupled receptor (GPCR) heteromers on the surface of cells.

The study, published in the Journal of Biological Chemistry, is based on the work by senior author Associate Professor Kevin Pfleger and colleagues.

Pfleger co-invented the technology to identify and study GPCRs, a family of receptors present on the outside of all cell membranes that enable cells to respond to hormones and neurotransmitters.

This GPCR family of receptors are extremely important in treating disease and are the target of up to 50 percent of all therapeutic drugs.

“Scientists now realize that these receptors do not work in isolation, but in particular combinations, which they call ‘heteromers’,” said Pfleger.

“It is suggested that a number of side effects from drugs may result from not fully understanding which combinations form and what happens when they do.”

Pfleger, who won the 2011 Australian Museum 3M Eureka Prize for Emerging Leader in Science, said prostate disorders such as benign prostatic hyperplasia affected nearly every man at some point in his life.

Better drugs with fewer side effects were needed to reduce or eliminate the need for surgical intervention in more serious cases, he said.

“We hope that the identification of this novel combination of receptors, and the novel functioning that results from their interaction, will provide opportunities to develop better treatments for debilitating prostate disorders that affect so many aging men,” Pfleger said.

The technology described here has been assigned to the UWA spin-out company Dimerix Bioscience for commercial development.

The article can be found at: Mustafa S et al. (2012) Identification and Profiling of Novel α1A-Adrenoceptor-CXC Chemokine Receptor 2 Heteromer.

Anusuya Das | Featured Research

AsianScientist

Source: UWA.