Scientists Find Protein That Turns Carbs Into Fat

By Emma Hitt, PhD

NEW YORK (Reuters Health) - Researchers have identified a small protein in liver cells that may help convert excess dietary carbohydrates into fat stores. They hope that the finding will lead to the development of obesity-fighting drugs that inhibit the actions of this protein.

A team led by Dr. Kosaku Uyeda, of the University of Texas Southwestern Medical Center at Dallas, identified the protein they call ChREBP in the liver of rats.

``When people eat desserts, pasta, potatoes or other sugar- and starch-laden foods beyond the body's energy and nutritional needs, these carbohydrates become a flood of glucose (sugar), and the liver converts the surplus glucose to fat,'' Uyeda explained in a written statement.

Uyeda's team determined whether ChREBP responded to excess dietary carbohydrates by feeding rats either a high-carbohydrate diet or a high-fat diet without starches. They found that the actions of ChREBP were enhanced with the high-carbohydrate diet, but not the high-fat diet.

These actions included increasing the activity of at least two and maybe three enzymes responsible for making fats out of excess carbohydrates, Uyeda told Reuters Health.

``Inhibition of ChREBP activation would be expected to (lessen) excess fat accumulation resulting from a high-carbohydrate diet and provide novel opportunities to address the health consequences stemming from obesity and diabetes,'' the researchers write in the July 31st issue of the Proceedings of the National Academy of Sciences (news - web sites).

``By developing drugs to inhibit the actions of this protein, we should slow down the conversion of excess carbohydrates to fat,'' Uyeda said. ``There is no medication that acts that way right now.''

But such a drug remains a while off, according to the researcher.

``Now we are just beginning to understand the structure and how this protein works,'' he said.

The next step, Uyeda added, is to isolate large quantities of the protein so that research into drug development can begin.

``But,'' he said, ``this may take several years.''

SOURCE: Proceedings of the National Academy of Sciences USA 2001;98:9116-

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