This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Gower, B. A. Articles by Goran, M. I. Search for Related Content PubMed PubMed Citation Articles by Gower, B. A. Articles by Goran, M. I.

Contribution of Insulin Secretion and Clearance to Glucose-Induced Insulin Concentration in African-American and Caucasian Children

Department of Nutrition Sciences and Clinical Nutrition Research Center (B.A.G., F.F.), Department of Critical Care (W.M.G.), Department of Pediatrics (F.F.), and Department of Health Services Administration (R.M.S.), University of Alabama at Birmingham, Birmingham, Alabama 35294-3360; and Departments of Preventive Medicine and Physiology and Biophysics, University of Southern California, and Institute for Prevention Research (M.I.G.), Los Angeles, California 90033

Address all correspondence and requests for reprints to: Dr. Barbara A. Gower, Department of Nutrition Sciences and Clinical Nutrition Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294-3360. E-mail: . bgower{at}uab.edu

Abstract

Relative to Caucasians (C), African-American (AA) children and adults have lower indices of insulin sensitivity (S_i) and a higher acute insulin response to glucose (AIR_g). Among AA children, AIR_g is greater than that which would be predicted based on lower S_i. The objectives of the present study were 1) to determine whether insulin secretory parameters differ in AA vs. C children and adolescents using C-peptide modeling, 2) to determine whether hepatic insulin extraction differs with ethnicity/race using the C-peptide to insulin molar ratio, and 3) to determine whether the relatively greater AIR_g among African-Americans is due to greater insulin secretion or lesser clearance. Subjects (n = 76) were AA and C children (mean age, 11 yr). A 3-h tolbutamide-modified iv glucose tolerance test and minimal modeling were used to determine S_i and AIR_g. First phase C-peptide/insulin secretion and basal, first, and second phase ß-cell sensitivity to glucose were determined using C-peptide modeling with standard kinetic parameters developed in adults. The incremental C-peptide to insulin molar ratio over the 3-h test period, an index of hepatic insulin extraction, was calculated with the trapezoidal method. S_i was lower and AIR_g was higher in AA vs. C children. First phase C-peptide/insulin secretion and first phase ß-cell sensitivity to glucose were approximately 2-fold greater in AA vs. C children (P < 0.001); there were no between-group differences in basal or second phase ß-cell sensitivity to glucose. Hepatic insulin extraction was lower in AA vs. C (3.77 ± 1.78% vs. 5.99 ± 2.18%; P < 0.001). Multiple linear regression modeling indicated that first phase C-peptide/insulin secretion and hepatic insulin extraction contributed independently to AIR_g; however, it was only first phase C-peptide/insulin secretion that explained the significant independent contribution of ethnicity/race to AIR_g after adjusting for S_i. The results of this study suggest that greater AIR_g among AA is due to both greater insulin secretion and lesser hepatic insulin extraction, and that AIR_g above that predicted based on lower S_i is due to greater insulin secretion. The insulin secretion data await verification that the kinetic parameters used apply to children and AA.

This article has been cited by other articles:

				J. A Alvarez, P. B Higgins, R. A Oster, J. R Fernandez, B. E Darnell, and B. A Gower Fasting and postprandial markers of inflammation in lean and overweight children Am. J. Clinical Nutrition, April 1, 2009; 89(4): 1138 - 1144. [Abstract] [Full Text] [PDF]

				P. B Higgins, J. R Fernandez, W T. Garvey, W. M Granger, and B. A Gower Entero-insular axis and postprandial insulin differences in African American and European American children Am. J. Clinical Nutrition, November 1, 2008; 88(5): 1277 - 1283. [Abstract] [Full Text] [PDF]

				S. Sam, A. D. Coviello, Y.-A. Sung, R. S. Legro, and A. Dunaif Metabolic Phenotype in the Brothers of Women with Polycystic Ovary Syndrome Diabetes Care, June 1, 2008; 31(6): 1237 - 1241. [Abstract] [Full Text] [PDF]

				P. A. Velasquez-Mieyer, P. A. Cowan, S. Perez-Faustinelli, R. Nieto-Martinez, C. Villegas-Barreto, E. A. Tolley, R. H. Lustig, and B. S. Alpert Racial Disparity in Glucagon-Like Peptide 1 and Inflammation Markers Among Severely Obese Adolescents Diabetes Care, April 1, 2008; 31(4): 770 - 775. [Abstract] [Full Text] [PDF]

				R. H. Willemsen, S. W. K. de Kort, D. C. M. van der Kaay, and A. C. S. Hokken-Koelega Independent Effects of Prematurity on Metabolic and Cardiovascular Risk Factors in Short Small-for-Gestational-Age Children J. Clin. Endocrinol. Metab., February 1, 2008; 93(2): 452 - 458. [Abstract] [Full Text] [PDF]

				N. Rasouli, H. J. Spencer, A. A. Rashidi, and S. C. Elbein Impact of Family History of Diabetes and Ethnicity on -Cell Function in Obese, Glucose-Tolerant Individuals J. Clin. Endocrinol. Metab., December 1, 2007; 92(12): 4656 - 4663. [Abstract] [Full Text] [PDF]

				S. P. Kim, M. Ellmerer, E. L. Kirkman, and R. N. Bergman beta-Cell "rest" accompanies reduced first-pass hepatic insulin extraction in the insulin-resistant, fat-fed canine model Am J Physiol Endocrinol Metab, June 1, 2007; 292(6): E1581 - E1589. [Abstract] [Full Text] [PDF]

				E. S. Ford, C. Li, G. Imperatore, and S. Cook Age, Sex, and Ethnic Variations in Serum Insulin Concentrations Among U.S. Youth: Findings from the National Health and Nutrition Examination Survey 1999-2002 Diabetes Care, December 1, 2006; 29(12): 2605 - 2611. [Abstract] [Full Text] [PDF]

				A. Brehm, K. Thomaseth, E. Bernroider, P. Nowotny, W. Waldhausl, G. Pacini, and M. Roden The Role of Endocrine Counterregulation for Estimating Insulin Sensitivity from Intravenous Glucose Tolerance Tests J. Clin. Endocrinol. Metab., June 1, 2006; 91(6): 2272 - 2278. [Abstract] [Full Text] [PDF]

				J. B Albu, A. J Kovera, L. Allen, M. Wainwright, E. Berk, N. Raja-Khan, I. Janumala, B. Burkey, S. Heshka, and D. Gallagher Independent association of insulin resistance with larger amounts of intermuscular adipose tissue and a greater acute insulin response to glucose in African American than in white nondiabetic women Am. J. Clinical Nutrition, December 1, 2005; 82(6): 1210 - 1217. [Abstract] [Full Text] [PDF]

				N. C. Bush, B. E. Darnell, R. A. Oster, M. I. Goran, and B. A. Gower Adiponectin Is Lower Among African Americans and Is Independently Related to Insulin Sensitivity in Children and Adolescents Diabetes, September 1, 2005; 54(9): 2772 - 2778. [Abstract] [Full Text] [PDF]

				S. Ten and N. Maclaren Insulin Resistance Syndrome in Children J. Clin. Endocrinol. Metab., June 1, 2004; 89(6): 2526 - 2539. [Abstract] [Full Text] [PDF]

				L. S. Conwell, S. G. Trost, W. J. Brown, and J. A. Batch Indexes of Insulin Resistance and Secretion in Obese Children and Adolescents: A validation study Diabetes Care, February 1, 2004; 27(2): 314 - 319. [Abstract] [Full Text] [PDF]

				D. J. Klein, L. Aronson Friedman, W. R. Harlan, B. A. Barton, G. B. Schreiber, R. M. Cohen, L. C. Harlan, and J. A. Morrison Obesity and the Development of Insulin Resistance and Impaired Fasting Glucose in Black and White Adolescent Girls: A longitudinal study Diabetes Care, February 1, 2004; 27(2): 378 - 383. [Abstract] [Full Text] [PDF]

				X. Chen, T. O. Scholl, M. J. Leskiw, M. R. Donaldson, and T. P. Stein Association of Glutathione Peroxidase Activity with Insulin Resistance and Dietary Fat Intake during Normal Pregnancy J. Clin. Endocrinol. Metab., December 1, 2003; 88(12): 5963 - 5968. [Abstract] [Full Text] [PDF]

				M. I. Goran, G. D. C. Ball, and M. L. Cruz Obesity and Risk of Type 2 Diabetes and Cardiovascular Disease in Children and Adolescents J. Clin. Endocrinol. Metab., April 1, 2003; 88(4): 1417 - 1427. [Abstract] [Full Text] [PDF]

				B. A. Gower, J. R. Fernandez, T. M. Beasley, M. D. Shriver, and M. I. Goran Using Genetic Admixture to Explain Racial Differences in Insulin-Related Phenotypes Diabetes, April 1, 2003; 52(4): 1047 - 1051. [Abstract] [Full Text] [PDF]