Effect of Dietary Nonstructural Carbohydrate Content on Activation of 5′‐Adenosine Monophosphate‐Activated Protein Kinase in Liver, Skeletal Muscle, and Digital Laminae of Lean and Obese Ponies

Journal of Veterinary Internal Medicine

T.A. Burns²  M.R. Watts²  P.S. Weber¹  L.J. McCutcheon¹  R.J. Geor¹ 

[1] Michigan State University College of Veterinary Medicine, East Lansing, MI;The Ohio State University College of Veterinary Medicine, Columbus, OH

关键词: Energy regulation;    Equine metabolic syndrome;    Insulin resistance;    Laminitis;   

DOI  :  10.1111/jvim.12356

来源: Wiley

【 摘 要 】

Abstract

Background

In EMS-associated laminitis, laminar failure may occur in response to energy failure related to insulin resistance (IR) or to the effect of hyperinsulinemia on laminar tissue. 5′-Adenosine-monophosphate-activated protein kinase (AMPK) is a marker of tissue energy deprivation, which may occur in IR.

Hypothesis/Objectives

To characterize tissue AMPK regulation in ponies subjected to a dietary carbohydrate (CHO) challenge.

Animals

Twenty-two mixed-breed ponies.

Methods

Immunohistochemistry and immunoblotting for total AMPK and phospho(P)-AMPK and RT-qPCR for AMPK-responsive genes were performed on laminar, liver, and skeletal muscle samples collected after a 7-day feeding protocol in which ponies stratified on body condition score (BCS; obese or lean) were fed either a low-CHO diet (ESC + starch, approximately 7% DM; n = 5 obese, 5 lean) or a high-CHO diet (ESC + starch, approximately 42% DM; n = 6 obese, 6 lean).

Results

5′-Adenosine-monophosphate-activated protein kinase was immunolocalized to laminar keratinocytes, dermal constituents, and hepatocytes. A high-CHO diet resulted in significantly decreased laminar [P-AMPK] in lean ponies (P = .03), but no changes in skeletal muscle (lean, P = .33; obese, P = .43) or liver (lean, P = .84; obese, P = .13) [P-AMPK]. An inverse correlation existed between [blood glucose] and laminar [P-AMPK] in obese ponies on a high-CHO diet.

Conclusions and Clinical Importance

Laminar tissue exhibited a normal response to a high-CHO diet (decreased [P-AMPK]), whereas this response was not observed in liver and skeletal muscle in both lean (skeletal muscle, P = .33; liver, P = .84) and obese (skeletal muscle, P = .43; liver, P = .13) ponies.

【 授权许可】

Unknown   
Copyright © 2014 by the American College of Veterinary Internal Medicine