Health

Hamster 'Roid Rage

By Robert Roy Britt, LiveScience Managing Editor

posted: 15 March 2006 07:18 am ET

If you put a hamster on steroids, he'll attack other hamsters more quickly and more often, and bite a lot. Cut him off and you might think he'd mellow out.

Not so. Hamsters on steroids remain aggressive into adulthood, according to a new study that offers yet another caution to teens who might try to bulk up artificially.

The hamsters started out tame. Then they were put on anabolic steroids and, as studies have shown with teens, the rodents exhibited "very high levels" of aggression, said study leader Richard Melloni, Jr. of Northeastern University.

Long after the more than 100 hamsters were taken off the steroids, the aggressive tendencies, or "'roid rage" as scientists put it, remained in 85 percent of them.

"The behavior lasted for weeks into the adult period in hamsters," Melloni told LiveScience. "Typically weeks translates into years from rodent to primate."

Autopsies revealed their brains had changed. The anterior hypothalamus, known to regulate aggression, pumped out more of a neurotransmitter called vasopressin.

"Steroids step on the gas for aggression by enhancing the activity of brain areas that induce aggression," Melloni said, adding that this brain area is similar in rodents and humans. "Some of the effects may wear off after withdrawal, but aggressive behavior won't stop immediately, leaving them to be a danger to themselves and others."

The results are detailed in the latest issue of the journal Behavioral Neuroscience.

According to the National Institute on Drug Abuse, about half a million teens abuse anabolic-androgenic steroids. Other research has shown teen use can lead to psychiatric problems and heavier steroid use later in life.

Melloni said other research that his team has not yet published indicates that drug use by teenagers causes irreversible changes in serotonin levels, which play a part in depression.