Basal and Insulin Mediated VLDL-Triglyceride Kinetics in Type 2 Diabetic Men

  1. Søren Nielsen1
  1. 1Department of Endocrinology and Internal Medicine, University Hospital, Aarhus, Denmark;
  2. 2Department of Nuclear Medicine, University Hospital, Aarhus, Denmark;
  3. 3Department of Clinical Pharmacology, University of Aarhus, Aarhus, Denmark.
  1. Corresponding author: Søren Nielsen, nielsen.soren{at}dadlnet.dk.

Abstract

OBJECTIVE Increased very-low-density lipoprotein triglycerides (VLDL-TG) concentration is a central feature of diabetic dyslipidemia. The objective was to compare basal and insulin mediated VLDL-TG kinetics, oxidation, and adipose tissue storage in type 2 diabetic and healthy (nondiabetic) men.

RESEARCH DESIGN AND METHODS Eleven type 2 diabetic and 11 healthy men, matched for BMI and age, were included. Ex vivo-labeled VLDL-TG tracers, blood and breath samples, fat biopsies, indirect calorimetry, and body composition measures were applied to determine VLDL-TG kinetics, VLDL-TG fatty acids (FA) oxidation, and storage in regional adipose tissue before and during a hyperinsulinemic euglycaemic clamp.

RESULTS VLDL-TG secretion was significantly greater in diabetic compared with healthy men (basal: 86.9 [31.0] vs. 61.9 [30.0] μmol/min, P = 0.03; clamp: 60.0 [26.2] vs. 34.2 [17.9] μmol · min−1, P = 0.01). The insulin mediated suppression of VLDL-TG secretion was significant in both groups. VLDL-TG clearance was lower in diabetic men (basal: 84.6 [32.7] vs. 115.4 [44.3] ml · min−1, P = 0.08; clamp: 76.3 [30.6] vs. 119.0 [50.2] ml · min−1, P = 0.03). During hyperinsulinemia fractional VLDL-TG FA oxidation was comparable, but in percentage of energy expenditure (EE), significantly higher in diabetic men. Basal VLDL-TG storage was similar, but significantly greater in abdominal compared with leg fat.

CONCLUSIONS Increased VLDL-TG in type 2 diabetic men is caused by greater VLDL-TG secretion and less so by lower VLDL-TG clearance. The ability of hyperinsulinemia to suppress VLDL-TG secretion appears preserved. During hyperinsulinemia VLDL-TG FA oxidation is significantly increased in proportion of EE in type 2 diabetic men. Greater basal abdominal VLDL-TG storage may help explain the accumulation of upper-body fat in insulin-resistant individuals.

Footnotes

  • Clinical trial reg. no. NCT01037647, clinicaltrials.gov.

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • Received April 21, 2010.
  • Accepted September 11, 2010.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.

| Table of Contents

This Article

  1. Diabetes vol. 60 no. 1 88-96
  1. All Versions of this Article:
    1. db10-0564v1
    2. 60/1/88 most recent