Another week, another appetite suppressing mechanism discovered. While recent research has been exploding with new discoveries, giving us greater understandings into the body's appetite mechanisms, rarely are these processes successfully manipulated. A new study from Imperial College London has taken the usual research one step further and successfully found a way to target specific thyroid hormones in the brain and manipulate appetite in mouse subjects with no side effects.

The research focused on thyroid hormones, as they are widely known to have a major role in regulating appetite. The problem previously faced by researchers has been the wide dispersal of thyroid hormone receptors (TRs) throughout the body. As thyroid hormones regulate a multitude of things in the body, a highly targeted method needed to be developed to specifically tackle the appetite mechanism.

The team looked at how they could specifically disable the activity of thyroid hormone receptors in the hypothalamus, a known appetite-regulating area of the brain.

This study split 21 mice into two groups, one control group and a second that was injected with a virus that specifically inactivated TRs in the hypothalamus. The results were very clear. The mice with inactive TRs doubled in weight over six weeks while the mice in the control group with active TRs maintained a stable weight over the study period.

Most significantly the study found that no other observable side effects were noted from the specific disabling of TRs in the hypothalamus. This is the first time researchers have been able to so specifically target an area of the brain and study the subsequent effects. Previous research as been able to more broadly deactivate TRs, but not without significant side effects.

"Our hope is that these findings could ultimately lead towards drugs that target thyroid hormones to reduce someone's appetite and help them control their weight," says Dr James Gardiner, lead author of the study.

Previous research has shown that lowered TR activity in the human brain is linked with obesity. The long-term outcome from this research could be the development of a medication that can activate TRs in those with diminished activity thus suppressing an overactive appetite. It is worth stressing that the phrase "long-term" is not used lightly here. The researchers note that their discovery is still in its very early stages.

"Due to the justifiably long and complex process of drug discovery, any potential treatment that could result from this will be far off in the future," Dr Gardiner notes. "However, the strength of our results, and the doubling in body size of these mice, shows that the role of thyroid hormones and their receptors are definitely worth exploring further in the fight against obesity."

The research was published in the journal Cell Reports.