Differential responses of IGF-I molecular complexes to military operational field training
| Autor: | M. Javad Khosravi, Bradley C. Nindl, Scott J. Montain, Anastasia Diamandi, Andrew J. Young, John W. Castellani, John F. Patton |
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| Rok vydání: | 2003 |
| Předmět: |
Adult
Male medicine.medical_specialty Physiology medicine.medical_treatment Nutritional Status Insulin-like growth factor-binding protein chemistry.chemical_compound Absorptiometry Photon Physiology (medical) Internal medicine medicine Glycerol Humans Insulin-Like Growth Factor I chemistry.chemical_classification biology Growth factor Metabolism Bioavailability Ferritin Insulin-Like Growth Factor Binding Proteins Transthyretin Endocrinology Military Personnel chemistry Transferrin Physical Fitness biology.protein Body Composition Sleep Deprivation Energy Intake Energy Metabolism Food Deprivation Biomarkers |
| Zdroj: | Journal of applied physiology (Bethesda, Md. : 1985). 95(3) |
| ISSN: | 8750-7587 |
| Popis: | Insulin-like growth factor (IGF) I and IGF binding proteins (IGFBPs) modulate metabolic activity and tissue repair and are influenced by nutritional status. IGF-I circulates in free, ternary [IGF-I + IGFBP-3 + acid labile subunit (ALS)], and binary (IGF-I + IGFBP) molecular complexes, and the relative proportions regulate IGF-I extravascular shifting and bioavailability. This study examined the hypothesis that sustained physical activity and sleep deprivation superimposed on a short-term energy deficit would alter the IGFBP concentrations and alter the proportions of IGF-I circulating in ternary vs. binary molecular complexes. Components of the IGF-I system (total and free IGF-I; IGFBP-1, -3, and ALS; nonternary IGF-I and IGFBP-3), biomarkers of metabolic and nutritional status (transferrin, ferritin, prealbumin, glucose, free fatty acids, glycerol, beta-hydroxybutyrate), and body composition were measured in 12 men (22 +/- 3 yr, 87 +/- 8 kg, 183 +/- 7 cm, 20 +/- 5% body fat) on days 1, 3, and 4 during a control and experimental (Exp) period. During Exp, subjects performed prolonged work (energy expenditure of approximately 4500 kcal/day) with caloric (1600 kcal/day) and sleep (6.2 h total) restriction. IGF-I and IGFBP-3 were measured by immunoassay before and after immunoaffinity depletion of ALS-based complexes (i.e., ternary complex removal). Exp produced losses in body mass (-3.0%), lowered total IGF-I (-24%), free IGF-I (-42%), IGFBP-3 (-6%), nonternary IGF-I (-27%), and IGFBP-3 (-16%), and increased IGFBP-1 (256%). No Exp effects were observed for ALS. No changes were observed in the proportion of IGF-I circulating in free ( approximately 1.2%), ternary ( approximately 87.4%), or nonternary ( approximately 11.4%) molecular complexes. During Exp, glucose concentrations were lower on day 3, but days 1 and 4 were statistically similar. In conclusion, during a short-term energy deficit in young, healthy men, 1). IGF-I system components differentially respond (both in direction and magnitude) to a given metabolic perturbation and 2). the relative proportion of IGF-I sequestered in ternary vs. nonternary molecular complexes appears to be well maintained. |
| Databáze: | OpenAIRE |
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