Leptin Downregulates Specific Liver Enzyme Causing Leanness, Hypermetabolism
NEW YORK (Reuters Health) Jul 12 - Scientists at The Rockefeller University in New York report that they have identified a specific hepatic enzyme that is downregulated by the leptin gene, which leads to leaner animals that have more energy expenditure.
Suppression of RNA synthesis of hepatic stearoyl-CoA desaturase-1 (SCD-1) resulted in the changes, according to the report in the July 12th issue of Science by Dr. Jeffrey M. Friedman and colleagues at Rockefeller and at the University of Wisconsin, Madison.
The team found that found that leptin-deficient (ob/ob) mice who were also deficient in SCD-1 had a 40% reduction in body mass and a 75% increase in energy expenditure compared with ob/ob controls who did not have a decreased expression of the SCD-1 gene. The SCD-1 deficient mice had very low triglyceride and VLDL cholesterol production and livers that were histologically normal.
Dr. Friedman notes that the metabolic effects of leptin cannot be explained by food intake alone, as the findings published today show. "These data show that SCD-1 is required for the fully developed obese phenotype of ob/ob mice and suggest that a significant proportion of leptin's metabolic effects may result from inhibition of this enzyme."
The investigators speculate that downregulation of the SCD-1 enzyme reduces fatty acid biosynthesis by reducing intracellular malonyl CoA and is also accompanied by an increase in fatty acid oxidation.
Science 2002;297:240-243.
I like the 75% increase in energy expenditure and 40% loss in mass. Leptin is a very interesting topic to me. Anyone know of any good info on how to manipulate it?
NEW YORK (Reuters Health) Jul 12 - Scientists at The Rockefeller University in New York report that they have identified a specific hepatic enzyme that is downregulated by the leptin gene, which leads to leaner animals that have more energy expenditure.
Suppression of RNA synthesis of hepatic stearoyl-CoA desaturase-1 (SCD-1) resulted in the changes, according to the report in the July 12th issue of Science by Dr. Jeffrey M. Friedman and colleagues at Rockefeller and at the University of Wisconsin, Madison.
The team found that found that leptin-deficient (ob/ob) mice who were also deficient in SCD-1 had a 40% reduction in body mass and a 75% increase in energy expenditure compared with ob/ob controls who did not have a decreased expression of the SCD-1 gene. The SCD-1 deficient mice had very low triglyceride and VLDL cholesterol production and livers that were histologically normal.
Dr. Friedman notes that the metabolic effects of leptin cannot be explained by food intake alone, as the findings published today show. "These data show that SCD-1 is required for the fully developed obese phenotype of ob/ob mice and suggest that a significant proportion of leptin's metabolic effects may result from inhibition of this enzyme."
The investigators speculate that downregulation of the SCD-1 enzyme reduces fatty acid biosynthesis by reducing intracellular malonyl CoA and is also accompanied by an increase in fatty acid oxidation.
Science 2002;297:240-243.
I like the 75% increase in energy expenditure and 40% loss in mass. Leptin is a very interesting topic to me. Anyone know of any good info on how to manipulate it?