Détail de la notice
Titre du Document
Paradoxical changes of muscle glutamine release during hyperinsulinemia euglycemia and hypoglycemia in humans: Further evidence for the glucose-glutamine cycle
Auteur(s)
MEYER Christian ; WOERLE Hans J. ; GERICH John
Résumé
Insulin suppresses and counterregulatory hormones increase proteolysis. Therefore, if proteolysis were a major factor determining amino acid fluxes in plasma, one would expect release of glutamine into plasma to be suppressed by insulin under euglycemic conditions and to be stimulated under hypoglycemic conditions. However, release of glutamine into plasma remains unaltered or increases during euglycemic hyperinsulinemia and decreases during insulin-induced hypoglycemia. To investigate the mechanisms for these paradoxical observations and the role of skeletal muscle, we infused overnight fasted volunteers with [U-14C] glutamine and measured release of glutamine into plasma, its removal from plasma, and forearm glutamine net balance, fractional extraction, uptake and release during 4-hour euglycemic (-5.0 mmol/L, n = 7) and hypoglycemic (∼3.1 mmol/L, n = 8) hyperinsulinemic (∼230 pmol/L) clamp experiments. During the euglycemic clamps, plasma glutamine uptake and release (both P <.05) and forearm muscle glutamine fractional extraction (P <.05), uptake (P < .02) and release (P <.01) all increased, whereas forearm glutamine net balance remained unchanged. The increase in muscle glutamine release (from 1.85 ± 0.26 to 2.18 ± 0.30 μmol . kg-1 . min-1) accounted for approximately 60% of the increase in total glutamine release into plasma (from 5.54 ± 0.47 to 6.10 ± 0.64 μmol . kg-1 . min-1) and correlated positively with the increase in muscle
Editeur
Elsevier
Identifiant
ISSN : 0026-0495
Source
Metabolism, clinical and experimental A. 2004, vol. 53, n° 9, pp. 1208-1214 [7 pages] [bibl. : 40 ref.]
Langue
Anglais
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