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:4/24/2017)... ... April 24, 2017 , ... Michael Vick announced his retirement earlier this year ... former overall number one pick in the 2001 NFL Draft, to the Atlanta Falcons, ... for the most career rushing yards by a quarterback (6,109) and the most rushing ...
(Date:4/24/2017)... ... 24, 2017 , ... Ridgecrest Herbals makes it a point to lead the ... waste, and support renewable energy. They believe this is a crucial part of their ... for health issues, and maintain that destroying the environment in the pursuit of profit ...
(Date:4/24/2017)... , ... April 24, 2017 , ... ... Research Association’s Outstanding Public Communication of Education Research Award. The award honors scholars ... education communities. It recognizes a scholar who has demonstrated the capacity to deepen ...
(Date:4/24/2017)... ... ... Today, Bright Pink , a national non-profit organization focusing on the prevention and early ... Bright Pink is proud to announce Katie Thiede as their new Chief Executive Officer. In ... as Chairman of the Board and launched a national search to find a visionary new ...
(Date:4/24/2017)... ... April 24, 2017 , ... Sean Fay is the ... Bag, Sonicare Toothbrush, Juiceman Juicer, and the George Foreman Grill (which sold more than ... marketer in the last 25 years. , Now, due to changes in the broadcast ...
Breaking Medicine News(10 mins):
(Date:4/19/2017)... 2017 Global Surgical Drainage Device Market: Overview ... to remove excess liquid and air. The fluid to ... or lymph. Surgical drains are used in a wide ... surgery, cardiovascular surgery, neurosurgery, plastic surgery etc. Common use ... accumulation of fluid e.g. blood or pus. Surgical drains ...
(Date:4/19/2017)... Companion animal vaccines ... pets such as canine, avian and feline. ... such as Attenuated Live Vaccines, Conjugate Vaccines, Inactivated ... Recombinant Vaccines. Attenuated live vaccines are derived from ... have been weakend under laboratory conditions. Conjugate vaccines ...
(Date:4/18/2017)... 2017 Cogentix Medical, Inc. (NASDAQ: CGNT), a ... Uro/Gyn and Gynecology markets with innovative and proprietary products, ... March 31, 2017 after the market close on Tuesday, ... host a conference call and webcast to discuss its ... 2017 at 4:30 p.m. Eastern Time (3:30 p.m. Central ...
Breaking Medicine Technology: