An experimental compound called C75 can help suppress the appetite and promote weight loss, according to new research. But the results of tests on mice show that the compound is only effective in obese subjects and has only a short term effect on those of normal weight.
Dr M. Daniel Lane of Johns Hopkins University School of Medicine in Baltimore has been investigating the effects of C75 for several years. The molecule causes weight loss by blocking an enzyme called fatty acid synthase which is involved in storing energy, in turn tricking the brain into thinking that the body needs less to eat and thus stimulating weight loss.
Dr Lane's team had already discovered that a single injection caused both lean and obese mice to stop eating, but testing the two together showed that the effect of the compound was much shorter in lean mice, with food intake returning to normal or close to normal before the end of the study.
Dr Lane said that the lean mice became tolerant to the compound if given it on a daily basis, and so its effectiveness was negated. Obese mice continued to lose weight throughout the period of the study, and those which were genetically engineered to be obese - weighing two to three times more than normal mice - did not become resistant to the effects of C75.
Another group of obese mice, which weighed 30 to 40 per cent more than lean mice after being on a high-fat diet, did begin to show some resistance to C75, but only after they lost a substantial amount of weight, Dr Lane said.
Besides suppressing the urge to eat, C75 also seems to have an effect on the burning of calories, according to the findings published in the 19 February issue of the Proceedings of the National Academy of Sciences.
A group of obese mice that did not receive C75 but were only allowed to eat the same amount of calories as the obese mice on C75 also lost weight during the study. However, their weight losses were 24 to 50 per cent smaller than the mice on C75.
The hope is that the research eventually will lead to anti-obesity therapy for humans, but it is too early to know whether C75 or a similar compound would be safe and effective, said Dr Lane.