A new study has discovered that there is more than one way in which the date-rape drug-4-hydroxybutyrate (4-HB)-can be metabolised by the human body.

Ohio and Michigan researchers have determined new routes by which 4-HB- the naturally occurring brain chemical- is metabolised by the body.

"This is new and important information. It may provide new clues on how to counteract the drug's effects, or to enhance its metabolism and decrease toxicity for chronic abusers or victims of sexual assault," said Dr. K. Michael Gibson, at Michigan Technological University.

4-HB is a derivative of a major brain neurotransmitter in humans and other species. It occurs naturally in small amounts in the brains of most animals and humans.

In a rare genetic metabolic disorder, 4-HB accumulates in extremely high levels, causing significant developmental delays and seizures.

But 4-HB-also called gamma hydroxybutyrate or GHB-is best known and most feared when it is taken orally, because it is a drug that impairs the capacity to exercise judgment, like rohypnol and ketamine hydrochloride.

Thus, it can be used to facilitate acquaintance sexual assault, commonly called date rape.

The researchers analysed the chemicals produced by the breakdown of 4-HB in mice and rats, by using very sophisticated mass spectrometry approaches to identify previously unknown enzymes and pathways that appear to act on 4-HB and other similarly structured compounds.

They discovered that 4-HB is metabolised by two different chemical mechanisms or pathways.