Beta-cell function is a major contributor to oral glucose disposition in obese Japanese students

Endocr J. 2007 Dec;54(6):903-10. doi: 10.1507/endocrj.k07-016. Epub 2007 Nov 16.

Abstract

Determinants of glucose intolerance were studied in 163 obese Japanese young adults, 18 to 21 years old (43 females,120 males), who underwent 75-g oral glucose tolerance testing. Type 2 diabetes was newly diagnosed in 2.9% (n = 4); impaired fasting glucose (IFG) in 5.1% (n = 7); and impaired glucose tolerance (IGT) in 10.9% (n = 15). A homeostasis model assessment of insulin resistance (HOMA-IR) was used to estimate insulin sensitivity; beta-cell function during the first 30 min of the test was measured and defined as the insulinogenic index. This index was adjusted for insulin sensitivity, since this affects both beta-cell function and glucose disposition (disposition index). The relationship between insulinogenic index and 1/HOMA-IR was not hyperbolic. However, the disposition index (DI) was useful for the estimation of beta-cell function with the correct confirmation about it validity using beta-cell function index (BI). The association between insulin sensitivity and beta-cell function to glucose disposal, as measured by the area under the glucose curve (AUCg), was examined in all subjects. Insulin sensitivity was significantly related to AUCg (log HOMA-IR; R (2) = 0.142, p<0.0001). On the other hand, an inverse curvilinear relationship was observed between beta-cell function and AUCg (log(Delta I/Delta G)/HOMA-IR, R (2) = 0.411, p<0.0001). Thus, impaired beta-cell function, when estimated as DI, was strongly associated with impaired glucose disposal. In conclusion, our study showed that both insulin sensitivity and impaired beta-cell function are associated with impaired glucose metabolism, and that beta-cell function may be more important in determining glucose disposal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adolescent
  • Adult
  • Area Under Curve
  • Blood Glucose / metabolism
  • Cholesterol / blood
  • Cross-Sectional Studies
  • Female
  • Glucose / administration & dosage
  • Glucose / metabolism*
  • Glucose Intolerance
  • Glucose Tolerance Test
  • Humans
  • Insulin / blood
  • Insulin Resistance
  • Insulin-Secreting Cells / metabolism
  • Insulin-Secreting Cells / physiology*
  • Japan
  • Male
  • Obesity / blood
  • Obesity / metabolism*
  • Triglycerides / blood

Substances

  • Blood Glucose
  • Insulin
  • Triglycerides
  • Cholesterol
  • Glucose