Triclocarban: Antibacterial acts as endocrine disrupter, exacerbates the effects of natural testosterone,

[Guest guest]

Study described in news article is free online. Link and abstract follow

hereinbelow.

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Anti-Bacterial Additive Widespread In U.S. Waterways

The new findings suggest that triclocarban contamination is greatly

underreported. ... " Co-Occurrence of Triclocarban and Triclosan in U.S.

Water Resources " ...

http://www.jhsph.edu/publichealthnews/press_releases/2005/halden_triclocarban_tr\

iclosan.html

Triclocarban-containing products have been marketed broadly in the

United States ... The authors labeled as new their discovery that

triclocarban increased ...

http://www.dateline.ucdavis.edu/dl_detail.lasso?id=9918

Triclosan and triclocarban are small organic molecules that give

antimicrobial properties to personal-care products such as soap,

deodorant and toothpaste ...

http://transectpoints.blogspot.com/2007/02/triclosan-triclocarban-concern.html

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January 2, 2007

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Antibacterial acts as endocrine disrupter*

Researchers find that a widely used antibacterial compound amplifies

natural hormone effects.

http://pubs.acs.org/subscribe/journals/esthag-w/2008/jan/science/bw_triclocarban\

..html

Triclocarban, an antibacterial compound widely used for about 45 years

in personal-care and cleaning products such as soaps, lotions, and

sanitizing wipes, exacerbates the effects of natural testosterone,

according to a study published online November 29 in Endocrinology

(2007, DOI: 10.1210/en.2007-1057). Other known endocrine disrupters are

estrogenic, antiestrogenic, antiandrogenic, or androgen mimics.

In the new study, researchers from the University of California

and Yale University exposed human cells and live rats to either

triclocarban or one of a few other polychlorinated diphenyl urea

compounds, either alone or with testosterone, at levels similar to those

that can occur in people. Triclocarban amplified the effects of

testosterone, which is present in men, women, and children. In vitro

tests with human cells showed that the interaction of triclocarban and

testosterone was synergistic, including a signaling increase of 45% in

one test. In rats, the combination showed additive effects of increased

mass in several accessory sex organs.

About 1 million pounds of triclocarban are produced for the U.S. market

every year. The antimicrobial is widespread in U.S. waterways and

persists in municipal sludge used for fertilizer. Little is known about

the health effects of long-term, multiple sources of exposure to the

antibacterial compound and its structural cousins, says study coauthor

Bill Lasley, associate director of the Center for Health and the

Environment at the University of California . However, he and his

colleagues say the new evidence suggests that triclocarban and other

structurally similar substances may be playing a role in a wide range of

reproductive and developmental disorders.

---ROBERT WEINHOLD

Copyright © American Chemical Society

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1: http://endo.endojournals.org/cgi/rapidpdf/en.2007-1057v1.pdf

Endocrinology. 2007 Nov 29 [Epub ahead of print]

Triclocarban enhances testosterone action: A new type of endocrine

disruptor?

Chen J, Ahn KC, Gee NA, Mohamed MI, Duleba AJ, Zhao L, Gee SJ, Hammock

BD, Lasley BL.

Center for Health and the Environment (J.C., N.A.G., B.L.L), Department

of Entomology (K.C.A., S.J.G., B.D.H), California National Primate

Research Center (N.A.G., B.L.L.), Division of Reproductive Endocrinology

and Infertility, UCD Medical Center (A.J.D.), Department of Nutrition

(L.Z), Cancer Research Center (B.D.H.), University of California, ,

California 95616 and Department of Obstetrics and Gynecology (M.I.M.,

A.J.D.), Yale University School of Medicine, New Haven, Connecticut 06510.

Many xenobiotics have been associated with endocrine effects in a wide

range of biological systems. These associations are usually between

small non-steroid molecules and steroid receptor signaling systems. In

this report, triclocarban (TCC; 3,4,4'-trichlorocarbanilide), a common

ingredient in personal care products that is employed as an

antimicrobial agent was evaluated and found to represent a new category

of endocrine-disrupting substance (EDS). A cell-based androgen

receptor-mediated bioassay was used to demonstrate that TCC and other

urea compounds with a similar structure, which have little or no

endocrine activity when tested alone, act to enhance testosterone (T)

induced androgen receptor-mediated transcriptional activity in vitro.

This amplification effect of TCC was also apparent in vivo when 0.25%

TCC was added to the diet of castrated male rats that were supported by

exogenous testosterone treatment for ten days. All male sex accessory

organs increased significantly in size following the T+TCC treatment

compared to T or TCC treatments alone. The data presented here suggest

that the bioactivity of endogenous hormones may be amplified by exposure

to commercial personal care products containing sufficient levels of TCC.

PMID: 18048496

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