title: Aerobic exercise training increases circulating insulin-like growth factor binding protein-1 concentration, but does not attenuate the reduction in circulating insulin-like growth factor binding protein-1 after a high-fat meal.
abstract: Insulin-like growth factor binding protein-1 (IGFBP-1) has metabolic effects throughout the body, and its expression is regulated in part by insulin. Circulating IGFBP-1 predicts development of cardiometabolic diseases in longitudinal studies, and low IGFBP-1 concentrations are associated with insulin resistance and consumption of a high-fat diet. Because of the favorable metabolic effects of regular aerobic exercise, we hypothesized that aerobic exercise training would increase plasma IGFBP-1 concentrations and attenuate the reduction in IGFBP-1 after a high-fat meal. Ten overweight (body mass index = 28.7 ± 0.9 kg/m(2)), older (61 ± 2 years) men and women underwent high-fat feeding and oral glucose tolerance tests at baseline and after 6 months of aerobic exercise training. In response to aerobic exercise training, subjects increased cardiorespiratory fitness by 13% (P < .05) and insulin sensitivity index by 28% (P < .05). Basal plasma concentrations of IGFBP-1 increased by 41% after aerobic exercise training (P < .05). The insulin response to an oral glucose tolerance test was a significant predictor of fasting plasma IGFBP-1 concentrations at baseline and after exercise training (P = .02). In response to the high-fat meal at baseline, plasma IGFBP-1 concentrations decreased by 58% (P < .001); a 61% decrease to similar postprandial concentrations was observed after exercise training (P < .001). Plasma insulin response to the high-fat meal was inversely associated with postprandial IGFBP-1 concentrations at baseline and after exercise training (P = .06 and P < .05, respectively). Although aerobic exercise training did not attenuate the response to a high-fat meal, the increase in IGFBP-1 concentrations after exercise training may be one mechanism by which exercise reduces risk for cardiometabolic diseases in older adults.
authors.affiliation: Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA. sprior@grecc.umaryland.edu
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Prior
authors.forename: Nathan T
authors.initials: NT
authors.lastname: Jenkins
authors.forename: Josef
authors.initials: J
authors.lastname: Brandauer
authors.forename: Edward P
authors.initials: EP
authors.lastname: Weiss
authors.forename: James M
authors.initials: JM
authors.lastname: Hagberg
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001774:Blood Chemical Analysis; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D003864:Depression, Chemical; D004041:Dietary Fats / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010806:Physical Education and Training; D010809:Physical Fitness / Q000502:physiology
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1