I found this article at www.mydna.com – look there for the full article – Karen
 
 
 
 
Genetic complexities of obesity
 
 
Tue 11 Oct 2005 02:07 pm CST
NORTH CAROLINA
(myDNA News)
 
 
The gene encoding an enzyme that hinders muscle from burning fat manufactures three times more enzyme in the muscle of obese people than lean people, researchers from
Duke
University
Medical
Center
and
Louisiana
State
University
have found. This causes the obese muscle tissue to both store more fat and burn less fat, the researchers said.
 
 
"Obesity is a very complex disease, and this metabolic pathway does not fully explain obesity, but it is a likely contributor," said Deborah Muoio, Ph.D. Excess fat storage in muscle tissue is a hallmark of obesity, and may contribute to problems such as diabetes and cardiovascular disease. The researchers discovered that skeletal muscle tissue and cells from obese people were programmed to store fat even when removed from the body and forced to grow in the laboratory. This finding suggests the gene is more active in obese people not only because of excess calorie intake, but also as a result of heritable changes in its regulation, Muoio said.
 
 
"The cells of obese people remembered their metabolic program, which could help explain, in part, why losing weight and maintaining weight loss is so difficult," Muoio said. "The good news is it's possible to change your energy balance through exercise- can enhance muscle's ability to burn fat.
 
 
Muoio suspects that the gene's behavior is altered in obese people because of an alteration of gene activity states without variations in the DNA code. These changes can be triggered by environmental factors, such as nutrition or chemical exposure, and carried forward even after the stimulus is removed. The gene investigated in the study is present in obese and lean people, but was overexpressed, or more active, in obese muscle tissue and cells, which means the obese tissue produced larger quantities of enzyme.
 
 
…When the muscle satellite cells were encouraged to develop into mature muscle cells, they showed the same fat storage programming as muscle tissue. "This is a very important clue, because it indicates this program of fat storage is perpetuated as these cells divide. It's not driven strictly by over-nutrition," Muoio said…
 
 
"We found that obesity was associated with a threefold increase in SCD1 (a fat storing enzyme found in muscle tissue) expression in obese muscle, as well as a threefold higher level of SCD1 enzyme, compared to lean muscle," Muoio said. The activity of other genes linked to fat metabolism and obesity were comparable between the two groups.
 
 
The researchers also investigated how muscle cells from lean individuals behaved when forced to overproduce the SCD1 enzyme. Using genetic engineering techniques, the team showed that cells from lean people mimicked the metabolism of obese cells, storing more fat droplets and burning less fat, when the amount of SCD1 was increased.