Role of insulin and branched-chain amino acids in regulating protein metabolism during fasting
| Autor: | Paul J. Flakoll, M. L. Warner, Naji N. Abumrad, Nada Bulus, Maria Frexes-Steed |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Adult
Blood Glucose Male medicine.medical_specialty Epinephrine Hydrocortisone Physiology Endocrinology Diabetes and Metabolism Proteolysis medicine.medical_treatment Protein metabolism Biology chemistry.chemical_compound Leucine Physiology (medical) Internal medicine medicine Protein biosynthesis Humans Insulin Amino Acids Infusions Intravenous Pancreatic hormone chemistry.chemical_classification medicine.diagnostic_test Metabolism Fasting Glucagon Amino acid Endocrinology chemistry Amino Acids Branched-Chain |
| Zdroj: | The American journal of physiology. 258(6 Pt 1) |
| ISSN: | 0002-9513 |
| Popis: | This study examines the independent effects of insulin and amino acids on protein metabolism after a 12-h and 4-day fast in healthy volunteers. Leucine (Leu) kinetics were examined during sequential insulin infusions of 0 (group I) or 0.0125 (groups II and III), 1.2, and 10 mU.kg-1.min-1. Plasma Leu was maintained at 12-h fasted levels in groups I and II and at 84-h fasted levels in group III. Four-day fast (vs. 1 day, P less than 0.01) was associated with a 79% drop in plasma insulin and elevations in plasma Leu (122%), Leu rates of appearance (Ra) (21%), and Leu oxidation (56%), and no change in nonoxidative rates of disappearance (Rd). Insulin resulted in a dose-dependent suppression of endogenous Leu Ra with group III = I greater than II. Leu oxidation rose 1.7-fold in group III at the highest insulin dose but remained stable in the two other groups. In conclusion, 4-day fasting is associated with enhanced proteolysis and Leu oxidation with no change in nonoxidative Rd (protein synthesis). Elevated branched-chain (and other) amino acids were required to restore tissue sensitivity and specificity to the effects of insulin on protein metabolism after 4 days of fasting. |
| Databáze: | OpenAIRE |
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