Navigation Links
Low Doses Of Arsenic Have Broad Impact On Hormone Activity – Says A Researc

Dartmouth Medical School investigators are learning more about how low doses of arsenic, such as the levels found in drinking water in many areas of the United States//, affect human physiology. In a paper published online on Dec. 2 in the journal Chemical Research in Toxicology, the researchers report that three different steroid hormones all show similar responses to arsenic, suggesting a broader effect and a common mechanism of arsenic on how these hormones function.

"Since most of the health consequences of exposure to arsenic - various cancers, diabetes, heart and vascular disease, reproductive and developmental effects, etc. - involve these same steroid receptors, we think that disruption of their normal function could explain, in large part, how arsenic can influence so many disease risks," says Joshua Hamilton, one of the authors on this study and the director of the Center for Environmental Health Sciences at Dartmouth and Dartmouth's Superfund Basic Research Program on Toxic Metals.

Hamilton's laboratory had earlier found that arsenic disrupts the activity of the glucocorticoid receptor, and this follow up study considered the progesterone and mineralocorticoid receptors, which regulate a wide range of biological processes. This work was done in collaboration with Jack Bodwell, the lead author on this paper and a research associate professor of physiology at Dartmouth Medical School.

Hamilton, Bodwell, and their team found that arsenic appears to suppress the ability of all three of these critical receptors to respond to their normal hormone signals. Chemicals that disrupt steroid hormone receptor signaling are called endocrine disruptors, and this study provides further evidence that arsenic, a metal, does not behave like other endocrine disruptors such as pesticides.

"Arsenic does not activate these receptors, as some endocrine disruptors do, by mimicking the natural hormone, nor does it block the ability of the n ormal hormones to activate their specific receptor, as most other endocrine disruptors do," says Hamilton, who is also a professor of pharmacology and toxicology at Dartmouth Medical School. "Nor does it affect the ability of the hormone-activated receptor to move to the nucleus of the cell or to bind to DNA to initiate gene expression. Yet, somehow arsenic still strongly affects the ability of these hormone-activated receptors to regulate gene expression. There's still a lot more to learn."

The study also looked into the effects of different levels of arsenic on these receptors. At very low doses (comparable to what is found in drinking water at the current and previous U.S. regulatory limits, in the range of 5-50 ppb) arsenic enhances hormone-stimulated gene expression, by two- to three-fold. At slightly higher doses (in the range of 50-200 ppb, commonly found in drinking water from contaminated wells in New Hampshire and elsewhere in the U.S.) arsenic has the exact opposite effect, strongly and almost completely inhibiting hormone-stimulated gene expression by these receptors. This non-conventional dose-response suggests that arsenic might have very different biological effects at the lower and higher doses.

"Elucidating these complex biological effects of arsenic on hormone signaling at different doses will be critical to our overall understanding of how arsenic influences human health, and should be considered as an important component of determining the overall disease risk of people who are exposed to arsenic in their drinking water, " says Hamilton.

The work is funded by grants to Dartmouth collaborators Hamilton and Bodwell from the National Institute of Environmental Health Sciences, a component of the National Institutes of Health. Both researchers are members of the NIEHS-funded Superfund Basic Research Program at Dartmouth and Dartmouth's Center for Environmental Health Sciences. Co-authors on the study include Julie A. Go sse, and Athena P. Nomikos, both of Dartmouth and both recipients of training fellowships from Dartmouth's Superfund Basic Research Program.



Source-Eurekalert
SRI
'"/>




Related medicine news :

1. India To Procure 1 Million Doses Of Tamiflu
2. Small Doses Of Radiation Can Help Certain Lung Cancer Patients
3. Polyphenols in Green Tea Cause Liver Damage At High Doses
4. Pre-eclampsia Pronounced With Intake of Vitamins in Large Doses
5. Stronger Doses Fewer Administration for Breast Cancer
6. High Doses Of Common Pain killers Can Double The Chances Of Heart attack
7. Even Normal Doses Of Tylenol Could Damage Liver
8. Allergic Individuals Should Carry Two Doses Of EpiPen Says Quebec Coroner
9. Reduced Doses of Medication Beneficial to Preschoolers with ADHD
10. Low Doses of Anti-Depressant May Help PMS
11. High Doses of Lithium-Like Drugs May Impair Neuronal Function
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:1/24/2017)... ... 24, 2017 , ... TopConsumerReviews.com recently gave a best-in-class 5 ... or PMS . , Most women of child-bearing age will experience the symptoms ... headaches, fatigue, and other discomfort. For some women, the effects are severe ...
(Date:1/24/2017)... ... 2017 , ... “Choosing Wisdom-Solomon’s Proverbs Reclaimed”: an inspiring ... prostitution, adultery, anger, and common sense. , “Choosing Wisdom-Solomon’s Proverbs Reclaimed” is ... Coats. In September of 1983, they flew to Haiti to focus on missions ...
(Date:1/24/2017)... ... 24, 2017 , ... “Spiritual Vitamins: A Spiritual Energy Booster”: ... “Spiritual Vitamins: A Spiritual Energy Booster” is the creation of published author, Mathai ... new book engages the mind and spirit in a quest for fulfillment and ...
(Date:1/24/2017)... ... January 24, 2017 , ... “The Octagon of Spiritual ... Octagon of Spiritual Balances” is the creation of published author, Pastor Bernard J. Weathers, ... Weathers holds a bachelor degree in religious education and a master degree in theology. ...
(Date:1/24/2017)... ... January 24, 2017 , ... Attention women who want ... suggests that autologous fat grafting—taking one’s own fat and putting it in other ... , Cosmetic Surgeon and Medical Director of MilfordMD Cosmetic Dermatology Surgery & ...
Breaking Medicine News(10 mins):
(Date:1/24/2017)... Jan. 23, 2017 INTRODUCTION Injectable drug ... conventional syringes with vials to prefilled syringes, auto-injectors, ... devices have become preferred devices for parenteral administration ... has been rising strongly over the past several ... now adopting this format for delivering drugs. The ...
(Date:1/24/2017)... , January 23, 2017 ... for life sciences, announces agClinical 3.3, the latest version ... further enables life science organizations to confidently and efficiently ... and better manage the electronic trial master file so ... ...
(Date:1/23/2017)... NEW YORK , Jan. 23, 2017 ... Development Partners and Driving the Stability Testing Outsourcing Market ... testing market addresses market sizing, emerging trends, and technologies, ... the market. The base year is 2015 and forecasts ... market is expected to grow at a CAGR of ...
Breaking Medicine Technology: