Australian scientists may have discovered how to help people lose weight without cutting back on food, a breakthrough that could pave the way for fat-burning drugs.
Researchers in Melbourne found that by manipulating fat cells in mice they were able to speed up the animals' metabolisms.
They found that when a particular enzyme, known as angiotensin converting enzyme (ACE), was removed, mice were able to eat the same amount as other mice but burn more calories and therefore gain less weight.
Animals without the enzyme were on average 20 percent lighter than normal mice and had 50 to 60 percent less body fat, senior researcher at the Howard Florey Institute Michael Mathai said.
"It is very clear that they do have less body fat," he told AFP.
Mathai, who is also a lecturer in nutrition at Victoria University, said the slimmer mice also appeared to have less chance of developing diabetes because they processed sugar faster than normal mice.
He said the research, to be published Tuesday in the US-based Proceedings of the National Academy of Sciences, could be used to develop drugs to assist weight loss.
Drugs which impair the action of ACE already exist and are mostly used to combat high blood pressure.
"The drugs are out there because they are used for hypertension," he said.
"So we know their safety and their tolerability. What we don't know is whether or not they will work in humans. And we don't know whether it will work in all obese humans."
Mathai said it could be a question of finding the right dosage of hypertension medication, or developing a new type of drug of the same class, to be used as weight-loss pills.
"This might be one way in which you can increase metabolic rate in combination with managing nutrition to limit the intake of calories," he said.
Mathai said the research, conducted at the Howard Florey Institute, Victoria University, La Trobe University, Deakin University, the Baker Institute and the University of Melbourne, was yet to pinpoint why the genetic manipulation led to weight loss.
"Because we deleted the gene, the gene is gone from the whole body, that means that it is gone from all tissues including the brain," he said.
"And so we don't know whether it's a direct effect of the deficiency in the tissue or whether it's something coming from the brain."