[Pharmwaste] Male Fertility May Be Harmed By Mix Of Endocrine Disrupters

[DeBiasi,Deborah]

http://www.sciencedaily.com/releases/2008/02/080221121026.htm

Male Fertility May Be Harmed By Mix Of Endocrine Disrupters

ScienceDaily (Feb. 26, 2008) - Endocrine-disrupting chemicals, which are
harmless individually in small doses, can together be a dangerous
cocktail. Concurrent exposure to several endocrine-disrupting substances
may, among other things, result in malformed sexual organs. Risk
assessments of chemical substances should therefore take potential
cocktail effects into account.

Many young men have a low sperm count and more and more boys are born
with malformed sexual organs. A little less than five per cent of all
Danish boys are, for example, born with hypospadias, where the opening
of the urethra is on the underside of the penis. Substances disturbing
the hormonal balance during the foetal development have long been
suspected of being one of the causes of such birth defects.

"Several animal tests have shown that endocrine-disrupting chemicals,
which have an effect on the male sex hormone testosterone, can result in
such malformations in young male rats. In vitro testing and short-term
animal testing have also suggested that concurrent exposure to several
chemical substances can result in endocrine-disrupting effects even if
exposure to each individual substance does not show any effect. We are
now able to document that this is actually the case," says Ulla Hass,
senior scientist at the National Food Institute, Technical University of
Denmark.

Significant cocktail effects

The National Food Institute, Technical University of Denmark, has
carried out comprehensive studies in which pregnant rats were exposed to
a cocktail consisting of three chemicals that all inhibit the effect of
the male sex hormone testosterone: The drug flutamide and the pesticides
vinclozolin and procymidone.

The three chemicals were administered in doses which are harmless
individually. Concurrent exposure to the three substances did, however,
show significant cocktail effects. The male rats did, among other
things, develop female characteristics in the form of retained nipples
and severely malformed external sexual organs. Sixty per cent of the
male rats were, for example, born with hypospadias.

Underestimated risk

Today, risk assessments of chemicals and establishing reference values
are performed for one substance at a time although people are exposed to
many different chemical substances every day.

"Our studies show that concurrent exposure to several
endocrine-disrupting substances in small doses can increase the
frequency of malformations such as hypospadias even though the doses are
harmless individually. It is therefore not sufficient to establish
reference values only by looking at one substance at a time," concludes
Sofie Christiansen, PhD student at the National Food Institute,
Technical University of Denmark.

"In order not to underestimate the risk of chemicals to humans, it is
important to include the possible concurrent exposure of two or more
chemicals in the risk assessment. To establish an adequate protection
level for consumers, potential cocktail effects should be taken into
account, and thus the way a chemical may interact with other chemicals,"
adds Ulla Hass.

Journal reference: International Journal of Andrology:
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2605.2007.00866.
x

Adapted from materials provided by Technical University of Denmark, via
AlphaGalileo.


Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
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