New findings on implant compound could spell trouble

Oct 4, 2013

— Downstream behavior of chemical surprises researchers.

A chemical that breaks down in daylight but regains its abilities at night has been called a “zombie” in scientific circles. Those circles should check their science-fiction; neither mythological nor movie zombies are creatures of the night. “Vampire” perhaps, or “werewolf” might be more appropriate.

Regardless the playful name used to describe it, however, the finding could become a monster under the bed for the cattle world.

A recent study found elements of trenbolone acetate, an ingredient in some hormone implants used in beef cattle, do not permanently degrade as previously thought. Instead the elements—smaller particles called metabolites—reform to functional compounds at night. The resulting compound could cause problems to aquatic life. This could mean potential regulatory issues in the future.

“We’re finding a chemical that is broadly utilized, to behave in a way that is different from all our existing regulatory and risk-assessment paradigms,” explained co-corresponding author David Cwiertny, assistant professor in engineering at the University of Iowa.

Current knowledge on trenbolone acetate says that, when excreted into the environment by implanted cattle via urine, its metabolites quickly degrade and are rendered inactive. This seems to be true, but only when in contact with sunlight.

According to the study— “Product-to-Parent Reversion of Trenbolone: Unrecognized Risks for Endocrine Disruption”—trenbolone acetate metabolites reform when deprived of sunlight. In the dark, be that night time or in the deep regions of ponds, they regain their hormone-affecting abilities. And therein lies the potential problem, assuming the excreted trenbolone acetate reaches a body of water.

The study did not cover what effects the specific trenbolone acetate metabolites have on aquatic life, if any. However, prior research on similar compounds has found significant negative impacts to fish and other aquatic life. Things like skewed sex ratios in populations, impaired reproductive abilities and deformities have been documented.

Deborah Swackhamer of the University of Minnesota told Science magazine that the findings are “a potential game-changer” for ecological risk assessment.

The authors of the study agreed, saying the findings represent an important step towards understanding “the environmental role and impact of steroids and pharmaceutical products, all of which have been approved by the federal government for various uses and that have been shown to improve food availability, environmental sustainability and human health.”

Trenbolone acetate from cattle implants (as well as other sources) was not the only compound noted to have this ability to reform in the dark in the study. Other similar compounds such as dienogest and dienedone possessed the same reforming qualities.

Dienogest is an ingredient in a commercial form of human birth control and dienedone is an anabolic steroid which, though banned, is still marketed as a bodybuilding supplement. The presence of both of these compounds in the water systems can be attributed to humans. Like cattle can excrete trenbolone into the environment through their urine, so too can humans excrete dienogest and dienedone through urine.

“There are a variety of bioactive pharmaceuticals and personal-care products that we know are present in trace amounts in our water supply,” Cwiertny said. “We should use what we’re learning about trenbolone to more closely scrutinize the fate and better mitigate the impact of these products in the environment.”

What exactly these findings could mean for the beef and cattle industry is uncertain. Speaking to Science, a spokesperson for Merck, which produces implants containing trenbolone, pointed out “the implications of these findings to the environment remain undefined and theoretical.”

While true, there is considerable scientific documentation on the effects of hormone-affecting substances in aquatic life. And surprising new discoveries often spur increased interest in the scientific community so it is likely more research will come on this topic. It is possible the study and its findings may well help set the stage for a reassessment of the use of hormone implants in cattle in the future. — Kerry Halladay, WLJ Editor