| Obesity-Related Hormone
Obesity-Related Hormone
Joan Stephenson, PhD
JAMA. 2006;295:1239.
A rare mutation in a brain chemical called -melanocyte-stimulating hormone (-MSH) can increase a person's risk of severe early-onset obesity, according to new studies by European researchers (Lee YS et al. Cell Metab. 2006;3:135-140 and Biebermann H et al. Cell Metab. 2006;3:141-146).
One research team found that children with severe early-onset obesity were much likelier than children of normal weight to carry the rare -MSH mutation; moreover, overweight or obese relatives of children with the mutation were also more likely than normal-weight relatives to carry this gene variant. The group also discovered that the mutation altered the hormone's structure and its ability to stimulate the melanocortin-4 receptor, which previous research had demonstrated plays a critical role in controlling energy balance.
The second team also found the -MSH mutation in obese children, and that animals given the aberrant form -MSH do not reduce their food intake, unlike animals given the normal form of the hormone. A related chemical, -melanocyte-stimulating hormone (-MSH), suppresses appetite in both humans and rodents, but it has a strong stimulatory effect on sexual behavior that likely rules it out as a treatment for severe obesity. Because drugs that mimic -MSH might have different pharmacological properties, however, "they represent a new strategy to develop an anorexigenic compound without the side effects observed with -MSH," they said.
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