Effect of diet supplementation with glutamine, dihydroxyacetone, and leucine on food intake, weight gain, and postprandial glycogen metabolism of rats.
OBJECTIVE
We tested the hypothesis that increasing the rate of postprandial hepatic glycogen synthesis would decrease food intake and growth rate in normal rats.


METHODS
Diets supplemented with glutamine, glutamine plus dihydroxyacetone, and glutamine plus dihydroxyacetone plus leucine were administered to male Sprague-Dawley rats for 1 wk. These are combinations that have been shown to stimulate hepatic glycogen synthesis in vitro. Food intake and body weight were monitored throughout the experiment. At the end of the feeding period, rats were fed a test meal and injected with 3H2O to measure in vivo rates of glycogen and lipid synthesis. Positional analysis of the 3H incorporated into glycogen was used to determine the proportion of glycogen synthesized via pyruvate. Final levels of plasma glucose and triacylglycerol and hepatic glycogen were also measured.


RESULTS
Dietary glutamine increased hepatic glycogen synthesis. Addition of dihydroxyacetone, with or without additional leucine, caused an additional increase in hepatic glycogen synthesis and increased the proportion of glycogen synthesized via pyruvate. Lipogenesis was not altered in the liver or adipose tissue. None of the dietary treatments had any effect on food intake, but the diets that contained dihydroxyacetone decreased the rate of weight gain.


CONCLUSIONS
Increasing glycogen synthesis had no effect on food intake. Increasing the proportion of glycogen synthesized by the indirect pathway through pyruvate was associated with a decrease in weight gain.
Obeid
Omar A
OA
Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon.
Bittar
Sabrina T
ST
Hwalla
Nahla
N
Emery
Peter W
PW
D000818:Animals; D004098:Dihydroxyacetone / Q000008:administration & dosage* / Q000378:metabolism; D002149:Energy Intake / Q000187:drug effects*; D005973:Glutamine / Q000008:administration & dosage* / Q000378:metabolism; D007930:Leucine / Q000008:administration & dosage* / Q000378:metabolism; D050356:Lipid Metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008112:Liver Glycogen / Q000096:biosynthesis* / Q000378:metabolism; D008297:Male; D019518:Postprandial Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D014316:Tritium; D015430:Weight Gain / Q000187:drug effects*
D008112:Liver Glycogen; D005973:Glutamine; D014316:Tritium; D007930:Leucine; D004098:Dihydroxyacetone