• Open Access

Effects of the Insulin-Sensitizing Drug Pioglitazone and Lipopolysaccharide Administration on Insulin Sensitivity in Horses

Authors

  • J.K. Suagee,

    1. Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
    Search for more papers by this author
  • B.A. Corl,

    1. Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg, VA
    Search for more papers by this author
  • J.G. Wearn,

    1. Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA
    Search for more papers by this author
  • M.V. Crisman,

    1. Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA
    Search for more papers by this author
  • M.W. Hulver,

    1. Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA
    Search for more papers by this author
  • R.J. Geor,

    1. Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
    2. Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI
    Search for more papers by this author
  • L.J. McCutcheon

    1. Department of Biomedical and Veterinary Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA
    2. Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI
    Search for more papers by this author

  • This work was completed at the Middleburg Agricultural Research and Extension Center in Middleburg, VA 20117-3521. Presented at the 28th Forum of the American College of Veterinary Internal Medicine, Anaheim, CA, June 2010.

Corresponding author: B.A. Corl, Department of Dairy Science, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060-0315; e-mail: bcorl@vt.edu.

Abstract

Background: Obesity and insulin resistance increase the risk of laminitis in horses. Pioglitazone (PG) is an insulin-sensitizing drug used in humans that is absorbed after oral administration to horses.

Hypothesis: PG treatment will increase insulin sensitivity and transcript abundance of glucose and lipid transporters in adipose and skeletal muscle tissues.

Animals: Sixteen lean, healthy horses.

Methods: Eight horses were administered PG (1 mg/kg bodyweight PO) for 12 days before induction of insulin resistance through IV administration of lipopolysaccharide (LPS). Treated and untreated controls (CN; n = 8) were subjected to testing of peripheral insulin sensitivity and biopsies of both subcutaneous (nuchal ligament) adipose tissue and skeletal muscle before and after treatment, and 24 hours after LPS administration.

Results: PG treatment did not improve basal insulin sensitivity (CNs: 1.4 ± 0.3, PG-treated: 1.9 ± 1.3; P > .4) or mitigate LPS-induced insulin resistance (CNs: 0.4 ± 0.3, PG-treated: 0.4 ± 0.3); however, transcript abundance of glucose and lipid transporters was altered in both skeletal muscle and subcutaneous adipose tissue.

Conclusions and Clinical Importance: Either a higher dose or longer treatment period might be required for physiological effects to be observed. PG is a novel therapeutic agent requiring further investigation in horses in order to determine treatment efficacy.

Ancillary