US scientists have developed an anti-obesity vaccine that they say prevented weight gain in rats and could be helpful in finding a treatment for humans.
Researchers led by Professor Kim Janda at the Scripps Research Institute in California developed the vaccine that recognises different parts of ghrelin, a hormone that stimulates hunger and weight gain, reported online edition of BBC News.
Vaccinated rats put on less weight while eating the same amount as those which did not have the jab, it said.
The vaccinated rats gained less body weight, specifically body fat, and the reduction was associated with the levels of antibodies present.
The reduction in weight gain occurred despite the rats eating and drinking normally, indicating that the inhibition of ghrelin was having an effect on the animals' metabolism.
The researchers said the results demonstrated that active immunisation against ghrelin could be used to control weight gain and accumulation of fat tissue in mammals. The findings may help develop better treatment for humans, scientists say.
Many treatments for obesity have so far proved unsuccessful. Pharmaceutical companies have been looking for ways to block the action of ghrelin for years.
"What is surprising about this study is that by producing antibodies to block ghrelin it works as well as it does," said Professor Stephen Bloom at Imperial College London.