Featured Research

from universities, journals, and other organizations

Low Doses Of Arsenic Can Have Broad Impact On Hormone Activity

Date:
December 6, 2006
Source:
Dartmouth College
Summary:
Dartmouth 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.

Left to right: Dartmouth researchers Athena Nomikos, Jack Bodwell, Josh Hamilton, Julie Gosse
Credit: Photo by Joseph Mehling

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 normal 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. Gosse, and Athena P. Nomikos, both of Dartmouth and both recipients of training fellowships from Dartmouth's Superfund Basic Research Program.


Story Source:

The above story is based on materials provided by Dartmouth College. Note: Materials may be edited for content and length.


Cite This Page:

Dartmouth College. "Low Doses Of Arsenic Can Have Broad Impact On Hormone Activity." ScienceDaily. ScienceDaily, 6 December 2006. <www.sciencedaily.com/releases/2006/12/061204123351.htm>.
Dartmouth College. (2006, December 6). Low Doses Of Arsenic Can Have Broad Impact On Hormone Activity. ScienceDaily. Retrieved April 25, 2014 from www.sciencedaily.com/releases/2006/12/061204123351.htm
Dartmouth College. "Low Doses Of Arsenic Can Have Broad Impact On Hormone Activity." ScienceDaily. www.sciencedaily.com/releases/2006/12/061204123351.htm (accessed April 25, 2014).

Share This



More Health & Medicine News

Friday, April 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Companies Ramp Up Wellness to Lower Health Costs

Companies Ramp Up Wellness to Lower Health Costs

AP (Apr. 24, 2014) That little voice telling you to exercise, get in shape and get healthy is probably coming from your boss. More companies are beefing up wellness programs to try and cut down their health care costs. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
FDA Wants To Ban Sales Of E-Cigarettes To Minors

FDA Wants To Ban Sales Of E-Cigarettes To Minors

Newsy (Apr. 24, 2014) The Food and Drug Administration wants to crack down on the use of e-cigarettes, banning the sale of the product to minors. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins