http://news.bbc.co.uk/1/hi/health/874664.stm
8/10/2000
A molecular "switch" that controls the formation of fat cells has been discovered in mice.
The breakthrough could pave the way for future development of drugs to control obesity.
Scientists at the University of Michigan Medical School have discovered that when the switch is on fat cells do not develop.
However, when the switch is off even would-be muscle cells turns to fat.
The switch is made up of a type of protein known as a Wnt.
Wnts exist in all types of animals, and are known to regulate the changes that take place in the developing embryo in the womb.
However, the University of Michigan study is the first to identify the importance of Wnts in the formation of fat cells.
Lead researcher Dr Ormond MacDougald said: "Understanding this developmental pathway could help scientists learn how and why obesity develops."
Two types of cell
The researchers worked on two types of mouse cells - immature muscle cells called myoblasts and immature fat cells called preadipocytes.
In the absence of Wnt, both cell types consistently turned into fat cells.
Researcher Sarah Ross said: "During development, Wnt signalling seems to tell the cells, 'You're supposed to be a fat cell, you're supposed to be a muscle cell', and so forth.
"This signalling mechanism helps direct the cell's fate. If that toggle is switched the wrong way, then we see more fat formation."
The study was carried out on cultures of mouse cells. The researchers now plan to test the impact of Wnt on living mice.
Dr MacDougald said: "Our goal is to create a fat-free mouse."
He said that understanding the cellular events involved in fat cell formation "might suggest a series of targets to support the development of anti-obesity drugs, down the road".
However, he added: "It's not the cure for obesity next week.
"Obesity is a complicated problem and it's largely controlled by centres in the brain that control our appetite and also control whole-body energy metabolism."