Low-dose fructose boosts hepatic glycogen synthesis
Last Updated: 2001-07-06 14:06:08 EDT (Reuters Health)
By David Douglas
WESTPORT, CT (Reuters Health) – Low-dose fructose infusion leads to a threefold increase in hepatic glycogen synthesis in humans, a finding that may be of value in diabetes therapy, researchers report in the June issue of Diabetes.
Dr. Kitt Falk Petersen, of Yale University School of Medicine, New Haven, Connecticut, and colleagues note that in vitro and animal studies have suggested that a small amount of fructose may have a stimulating effect on hepatic glycogen metabolism, but whether this is the case in humans has hitherto remained unknown.
Dr. Peterson told Reuters Health that during conditions of euglycemia and hyperinsulinemia, glucose cycling leads to "very little glycogen being deposited in the liver. This is also the situation in poorly controlled diabetes."
To investigate, the researchers used nuclear magnetic resonance spectroscopy to assess rates of hepatic glycogen synthesis in six healthy volunteers. They were tested during euglycemic hyperinsulinemic conditions with and without a low-dose infusion of fructose.
In the fructose studies, although glycogen phosphorylase flux remained unchanged compared with control values, there was a threefold increase in rates of net hepatic glycogen synthesis, leading the researchers to conclude that it was achieved exclusively through stimulation of glycogen synthase flux.
"We are very excited about this study," Dr Peterson continued, and the finding that "tiny amounts of fructose act directly on the enzyme glycogen synthase and cause the liver to shunt glucose into liver glycogen," he added, has "potential implications for patients with poorly controlled type 1 and type 2 diabetes."
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