Arsenic: A New Kind Of Endocrine Disrupter?(and a risk factor for diabetes, cancer, and vascular disease)

2001 MAR 29 - (NewsRx.com & NewsRx.net) -- A team of Dartmouth Medical School investigators has uncovered what may be a unique mechanism for the way chronic exposure to low levels of arsenic increases the risk of certain diseases.

The work is described in the March 2001 issue of the journal Environmental Health Perspectives.

Arsenic at high doses has been known as the poison of choice since ancient times. Recently, it has become clear that decades of exposure to very low doses of arsenic - such as levels found in drinking water in many areas of the United States - may substantially increase the risk of vascular disease, diabetes, and several types of cancer. Until now, little was known about how arsenic might contribute to these diseases, however.

Using cultured animal cells, a team led by toxicologist Joshua Hamilton, director of Dartmouth's Toxic Metals Research Program, found that exposure to very low concentrations of arsenic disrupts the function of the glucocorticoid receptor, a steroid hormone receptor that regulates a wide range of biological processes. Arsenic appears to suppress the ability of this critical receptor to respond to its normal hormone signal. Chemicals that disrupt steroid hormone receptor signaling are called endocrine disrupters. Arsenic, a metal, appears to act through a unique mechanism not previously shown for other endocrine disrupters such as pesticides.

"This is unlikely to be the only mechanism underlying diseases associated with low-level arsenic exposure, but we suspect it will be an important contributor," says Hamilton.

The research was performed in Hamilton's laboratory in the Department of Pharmacology and Toxicology by former graduate student Ronald Kaltreider (now an assistant professor at York College in Pennsylvania) with the assistance of undergraduate student Alisa Davis and research assistant Jean Lariviere. The Toxic Metals group is one of the interdisciplinary research projects associated with the Center for Environmental Health Sciences at Dartmouth, which Hamilton also directs. The work is funded by a grant from the U.S. National Institute of Environmental Health Sciences and the Environmental Protection Agency through the ...