The contribution of dietary amino acids and endogenous hyperinsulinemia to prandial protein anabolism still has not been established. To this end, leucine estimates ([1- 14C]leucine infusion, plasma α-ketoisocaproic acid [KIC] specific activity [SA] as precursor pool SA) of whole-body protein kinetics and fractional secretory rates (FSRs) of albumin, fibrinogen, antithrombin III, and immunoglobulin G (IgG) were measured in three groups of healthy volunteers during intragastric infusion of water (controls, n = 5), liquid glucose–lipid–amino acid (AA) meal (meal+AA, n = 7), or isocaloric glucose–lipid meal (meal-AA, n = 7) that induced the same insulin response as the meal+AA. The results of this study demonstrate that 1) by increasing (P < 0.01) whole-body protein synthesis and decreasing (P < 0.01) proteolysis, dietary amino acids account for the largest part (∼90%) of postprandial protein anabolism; 2) the ingestion of an isocaloric meal deprived of amino acids exerts a modest protein anabolic effect (10% of postprandial protein anabolism) by decreasing amino acid oxidation and increasing (P < 0.01) albumin synthesis; 3) albumin FSR is increased (∼20%) by postprandial hyperinsulinemia (meal–AA) and additionally increased (∼50%) by amino acid intake (meal+AA); 4) IgG FSR is stimulated (∼40%) by amino acids, not by insulin; and 5) fibrinogen and antithrombin III FSR are not regulated by amino acids or insulin.
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Original Articles|
September 01 1996
Contribution of Amino Acids and Insulin to Protein Anabolism During Meal Absorption
Elena Volpi;
Elena Volpi
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Paola Lucidi;
Paola Lucidi
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Guido Cruciani;
Guido Cruciani
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Francesca Monacchia;
Francesca Monacchia
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Gianpaolo Reboldi;
Gianpaolo Reboldi
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Paolo Brunetti;
Paolo Brunetti
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Geremia B Bolli;
Geremia B Bolli
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Pierpaolo De Feo
Pierpaolo De Feo
Department of Internal Medicine, Endocrine and Metabolic Sciences, University of Perugia
Perugia, Italy
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Address correspondence and reprint requests to Dr. Pierpaolo De Feo, DI. M.I.S.E.M., Via E. Dal Pozzo, 06126 Perugia, Italy. [email protected]. unipg.it.
Diabetes 1996;45(9):1245–1252
Article history
Received:
November 21 1995
Revision Received:
May 02 1996
Accepted:
May 02 1996
PubMed:
8772730
Citation
Elena Volpi, Paola Lucidi, Guido Cruciani, Francesca Monacchia, Gianpaolo Reboldi, Paolo Brunetti, Geremia B Bolli, Pierpaolo De Feo; Contribution of Amino Acids and Insulin to Protein Anabolism During Meal Absorption. Diabetes 1 September 1996; 45 (9): 1245–1252. https://doi.org/10.2337/diab.45.9.1245
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