Dietary glutamine suppresses endogenous glutamine turnover in the rat.
Plasma glutamine turnover was determined using 1-14C-labeled glutamine in rats that consumed crystalline amino acid diets containing the equivalent of 16% protein with 25% of the amino acids as glutamine or a control diet containing no glutamine (or glutamate) for 10 days. Glutamine turnover in glutamine-fed animals was 66% of the rate in the control group. Glutamine feeding caused 20% higher levels of arterial plasma glutamine. Arterial-portal differences across the portal-drained viscera showed net glutamine uptake in control animals but no net uptake or release in the glutamine-fed group. Skeletal muscle glutamine synthetase activity was similar in both groups. The results indicate that long-term consumption of relatively large amounts of dietary glutamine decreases the turnover of plasma glutamine and thus reduces the need for endogenous glutamine synthesis.
Watford
M
M
Department of Nutritional Sciences, Cook College, Rutgers University, New Brunswick, NJ 08901-8525, USA.
Darcy-Vrillon
B
B
Duée
P H
PH
D000596:Amino Acids / Q000097:blood; D000818:Animals; D004032:Diet; D015536:Down-Regulation; D005973:Glutamine / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000596:Amino Acids; D011506:Proteins; D005973:Glutamine