Genes 'regulating obesity' in men found

Scientists have found genes that contribute to the risk of obesity in men.

A genome-wide linkage scan for high body mass index (BMI) in 3,893 men and 4,445 women has identified a link on chromosome 5q13-15.

Analysis of this chromosome has revealed a rare cluster of gene types linked to high BMI in men but not women. The portion of the chromosome related to high BMI risk contains a single gene named "arrestin domain containing 3" (Arrdc3).

Researchers investigated Arrdc3 expression and detected it in human fat and muscle. Analysis of gene expression in human abdominal fat biopsies showed significant correlation of Arrdc3 messenger RNA with BMI in men but not women, supporting the male-specific linkage to obesity.

The study also found that fasting increased Arrdc3 expression in both human and mouse fat tissue, suggesting that Arrdc3 functions to conserve energy when food is not available.

To test whether the gene causally regulates obesity, the scientist generated a mouse without Arrdc3. The mice without Arrdc3 showed a "striking resistance" to age-induced obesity: ale mice without Arrdc3 had a smaller total body mass compared to mice with the gene...