title: Differences in β-cell function and insulin secretion in Black vs. White obese adolescents: do incretin hormones play a role?
abstract: Black youth are at higher risk for type 2 diabetes (T2D) than their White peers. Previously we demonstrated that for the same degree of insulin sensitivity, Black youth have an upregulated β-cell function and insulin hypersecretion, in response to intravenous (iv) glucose, compared with Whites. To investigate if the same holds true during an oral glucose challenge and because of the important role of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) in augmenting insulin secretion, we examined β-cell function and incretin hormones in 85 Black and 78 White obese adolescents, with normal glucose tolerance (NGT), during a 2-h oral glucose tolerance test (OGTT) with mathematical modeling of plasma glucose and C-peptide concentrations to assess β-cell glucose sensitivity (βCGS), rate sensitivity, potentiation factor, and insulin sensitivity. Incretin, pancreatic polypeptide, and glucagon concentrations were measured during the OGTT. Black obese youth had a heightened early insulin secretion together with significantly greater βCGS, rate sensitivity, and potentiation factor compared with Whites, with no differences in incretin and glucagon concentrations. Basal and stimulated insulin clearance was lower (p = 0.001) in Black vs. White youth. In conclusion, during an OGTT Black obese youth with NGT demonstrate a pronounced early insulin secretion jointly with heightened β-cell glucose sensitivity, rate sensitivity, and potentiation factor. These racial disparities in β-cell function and the pathophysiological components of T2D are unlikely to be attributed to incretin hormones and remain to be investigated further to explain the metabolic basis for the enhanced risk of T2D in back youth.
authors.affiliation: Human Performance and Exercise Science, Youngstown State University, Youngstown, OH, USA.
authors.forename: Sara F
authors.initials: SF
authors.lastname: Michaliszyn
authors.affiliation: Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: SoJung
authors.initials: S
authors.lastname: Lee
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Fida
authors.initials: F
authors.lastname: Bacha
authors.affiliation: Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Hala
authors.initials: H
authors.lastname: Tfayli
authors.affiliation: Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Lama
authors.initials: L
authors.lastname: Farchoukh
authors.affiliation: CNR Institute of Neuroscience, Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mari
authors.affiliation: Department of Clinical and Experimental Medicine, University of Pisa School of Medicine, Pisa, Italy.
authors.forename: Ele
authors.initials: E
authors.lastname: Ferrannini
authors.affiliation: Division of Weight Management, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.|Division of Pediatric Endocrinology, Metabolism and Diabetes Mellitus, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Silva
authors.initials: S
authors.lastname: Arslanian
mesh_terms: D000293:Adolescent; D001741:Black or African American; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology / Q000378:metabolism; D005260:Female; D018149:Glucose Intolerance / Q000208:ethnology / Q000378:metabolism; D005951:Glucose Tolerance Test; D006801:Humans; D054795:Incretins / Q000378:metabolism / Q000502:physiology*; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000208:ethnology; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008297:Male; D063766:Pediatric Obesity / Q000208:ethnology* / Q000378:metabolism*; D012307:Risk Factors; D044465:White People
chemical_list: D054795:Incretins; D007328:Insulin
keywords: insulin secretion; modeling; race; youth; β-cell function