Contribution of amino acids and insulin to protein anabolism during meal absorption

Elena Volpi, Paola Lucidi, Guido Cruciani, Francesca Monacchia, Gianpaolo Reboldi, Paolo Brunetti, Geremia B. Bolli, Pierpaolo De Feo

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Abstract

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.

Original languageEnglish (US)
Pages (from-to)1245-1252
Number of pages8
JournalDiabetes
Volume45
Issue number9
DOIs
StatePublished - Jan 1 1996
Externally publishedYes

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ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

Cite this

Volpi, E., Lucidi, P., Cruciani, G., Monacchia, F., Reboldi, G., Brunetti, P., Bolli, G. B., & De Feo, P. (1996). Contribution of amino acids and insulin to protein anabolism during meal absorption. Diabetes, 45(9), 1245-1252. https://doi.org/10.2337/diab.45.9.1245