title: Behavioral, metabolic, and molecular correlates of lower insulin sensitivity in Mexican-Americans.
abstract: We determined whether lower insulin sensitivity persists in young, nonobese, nondiabetic Mexican-American [MA; n = 13, 27.0 +/- 2.0 yr, body mass index (BMI) 23.0 +/- 0.7] compared with non-Hispanic white (NHW; n = 13, 24.8 +/- 1.5 yr, BMI 22.8 +/- 0.6) males and females after accounting for cardiorespiratory fitness (maximal O(2) uptake), abdominal fat distribution (computed tomography scans), dietary intake (4-day records), and skeletal muscle insulin-signaling protein abundance from muscle biopsies (Western blot analysis). MA were significantly less insulin sensitive compared with their NHW counterparts when estimated by homeostatic model assessment of insulin resistance (MA: 1.53 +/- 0.22 vs. NHW: 0.87 +/- 0.16, P < 0.05) and the revised quantitative insulin sensitivity check index (MA: 0.45 +/- 0.08 vs. NHW: 0.58 +/- 0.19, P = 0.05). However, skeletal muscle protein abundance of insulin receptor-beta (IRbeta), phosphatidylinositol 3-kinase p85 subunit, Akt1, Akt2, and GLUT4 were not significantly different. Differences in indexes of insulin sensitivity lost significance after percent dietary intake of palmitic acid, palmitoleic acid, and skeletal muscle protein abundance of IRbeta were accounted for. We conclude that differences in insulin sensitivity between nonobese, nondiabetic MA and NHW persist after effects of chronic and acute exercise and total and abdominal fat distribution are accounted for. These differences may be mediated, in part, by dietary fat intake.
authors.affiliation: Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Ho
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Davy
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Hickey
authors.forename: Scott A
authors.initials: SA
authors.lastname: Summers
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Melby
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D004435:Eating / Q000502:physiology; D005260:Female; D051275:Glucose Transporter Type 4; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D017058:Mexican Americans; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000378:metabolism; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010809:Physical Fitness / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D062085:RNA, Long Noncoding; D011972:Receptor, Insulin / Q000378:metabolism; D014166:Transferases; D025521:Tumor Suppressor Proteins
chemical_list: D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D062085:RNA, Long Noncoding; D011972:Receptor, Insulin; D014166:Transferases; D025521:Tumor Suppressor Proteins; C109420:DLEU2 lncRNA, human; C495692:SLC2A4 protein, human; C494918:AKT1 protein, human; C494921:AKT2 protein, human