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The metabolic bases for "paradoxical" and normal feeding
D Novin1, L O'Farrell, A Acevedo-Cruz
1Department of Psychology, University of California, Los Angeles 90024-1563.
Brain Research Bulletin
|September 1, 1991
Summary
Rapid hexose infusion into the liver enhances hunger by promoting fat synthesis. Slow infusion promotes energy storage and satiety, highlighting infusion rate
Area of Science:
- Metabolism and Nutrition
- Gastroenterology
- Endocrinology
Background:
- Hexose (sugar) infusion into the digestive system or liver influences feeding behavior.
- Infusion rate significantly impacts whether hexoses reduce or increase food intake.
- Previous studies suggest a link between nutrient metabolism and satiety signals.
Purpose of the Study:
- To investigate the effect of hexose infusion rate on liver metabolism and feeding behavior.
- To determine the metabolic pathways affected by fast versus slow hepatic-portal hexose infusion.
- To correlate metabolic changes with alterations in hunger and satiety.
Main Methods:
- Infusion of glucose or fructose into the hepatic-portal vein at fast and slow rates.
- Measurement of 14C incorporation into liver mitochondria and glycogen.
- Assessment of tritiated water uptake into hepatic lipids.
Main Results:
- Fast hexose infusion increased hepatic lipid formation, decreased mitochondrial uptake and glycogen synthesis.
- Fast infusion was associated with enhanced hunger.
- Slow hexose infusion promoted substrate uptake into mitochondria and glycogen, with reduced lipid formation, correlating with satiety.
Conclusions:
- The rate of hexose delivery to the liver critically modulates metabolic pathways.
- Fast infusion promotes lipogenesis and hunger, while slow infusion favors oxidation and satiety.
- These findings support a metabolic basis for the regulation of appetite by nutrient sensing in the liver.