Pancreatic beta-cells in obesity. Evidence for induction of functional, morphologic, and metabolic abnormalities by increased long chain fatty acids.

Published

Journal Article

To elucidate the mechanism of the basal hyperinsulinemia of obesity, we perfused pancreata from obese Zucker and lean Wistar rats with substimulatory concentrations of glucose. Insulin secretion at 4.2 and 5.6 mM glucose was approximately 10 times that of controls, whereas beta-cell volume fraction was increased only 4-fold and DNA per islet 3.5-fold. We therefore compared glucose usage at 1.4, 2.8, and 5.6 mM. Usage was 8-11.4 times greater in Zucker islets at 1.4 and 2.8 mM and 4 times greater at 5.6 mM; glucose oxidation at 2.8 and 5.6 mM glucose was > 12 times lean controls. To determine if the high free fatty acid (FFA) levels of obesity induce these abnormalities, normal Wistar islets were cultured with 0, 1, or 2 mM long chain FFA for 7 days. Compared to islets cultured without FFA insulin secretion by FFA-cultured islets (2 mM) perifused with 1.4, 3, or 5.6 mM glucose was increased more than 2-fold, bromodeoxyuridine incorporation was increased 3-fold, and glucose usage at 2.8 and 5.6 mM glucose was increased approximately 2-fold (1 mM FFA) and 3-fold (2 mM FFA). We conclude that hypersecretion of insulin by islets of obese Zucker fatty rats is associated with, and probably caused by, enhanced low Km glucose metabolism and beta-cell hyperplasia, abnormalities that can be induced in normal islets by increased FFA.

Full Text

Duke Authors

Cited Authors

  • Milburn, JL; Hirose, H; Lee, YH; Nagasawa, Y; Ogawa, A; Ohneda, M; BeltrandelRio, H; Newgard, CB; Johnson, JH; Unger, RH

Published Date

  • January 20, 1995

Published In

Volume / Issue

  • 270 / 3

Start / End Page

  • 1295 - 1299

PubMed ID

  • 7836394

Pubmed Central ID

  • 7836394

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.270.3.1295

Language

  • eng

Conference Location

  • United States