Teenagers may be damaging their bodies and brains by binge drinking, US scientists said after tests showed adolescent rats exposed to high doses of alcohol suffered impaired growth and altered brain function.

The results were a warning to teenagers, the study's head, Dr Douglas Matthews from the University of Memphis, said. "These findings suggest adolescence is a unique developmental period where exposure to high alcohol levels can produce changes in biological functions that might have long-lasting implications."

The study defined "binge drinking" as five or more drinks in one session. The 30-day-old rats were exposed to an alcohol consumption pattern called chronic intermittent ethanol (CIE).CIE exposure produced a high level of alcohol tolerance in the rats which in some cases lasted into adulthood. It hampered normal growth, as measured by weight gain, and altered liver function.

Brain function was also affected, the study, published in the journalAlcoholism: Clinical & Experimental Research, found. Professor Linda Patia Spear, from Binghamton University, New York, said little was known about the effects of alcohol on teenagers. Available data was mixed, and studies often did not include adult comparison groups.

Dr Matthews' team now plans to study the effects of CIE exposure on the brain.