Insulin sensitivity in Belgian horses with polysaccharide storage myopathy.
Abstract: To determine insulin sensitivity, proportions of muscle fiber types, and activities of glycogenolytic and glycolytic enzymes in Belgians with and without polysaccharide storage myopathy (PSSM). Methods: 10 Quarter Horses (QHs) and 103 Belgians in which PSSM status had been determined. Methods: To determine insulin sensitivity, a hyperinsulinemic euglycemic clamp (HEC) technique was used in 5 Belgians with PSSM and 5 Belgians without PSSM. Insulin was infused i.v. at 3 mU/min/kg for 3 hours, and concentrations of blood glucose and plasma insulin were determined throughout. An i.v. infusion of glucose was administered to maintain blood glucose concentration at 100 mg/dL. Activities of glycogenolytic and glycolytic enzymes were assessed in snap-frozen biopsy specimens of gluteus medius muscle obtained from 4 Belgians with PSSM and 5 Belgians without PSSM. Percentages of type 1, 2a, and 2b muscle fibers were determined via evaluation of >or= 250 muscle fibers in biopsy specimens obtained from each Belgian used in the aforementioned studies and from 10 QHs (5 with PSSM and 5 without PSSM). Results: Belgians with and without PSSM were not significantly different with respect to whole-body insulin sensitivity, muscle activities of glycogenolytic and glycolytic enzymes, or proportions of muscle fiber types. However, Belgians had an increased proportion of type 2a and decreased proportion of type 2b muscle fibers, compared with proportions in QHs, regardless of PSSM status. Conclusions: PSSM in Belgians may be attributable to excessive glycogen synthesis rather than decreased glycogen utilization or enhanced glucose uptake into muscle cells.
Publication Date: 2008-06-04 PubMed ID: 18518664DOI: 10.2460/ajvr.69.6.818Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research studied insulin sensitivity, muscle fiber types, and the activity of certain enzymes in Belgian horses with and without a condition called polysaccharide storage myopathy (PSSM). The researchers found that the presence of PSSM in these horses did not significantly affect these variables, but all Belgian horses had a higher proportion of certain muscle fiber types compared to Quarter Horses. It was suggested that PSSM in Belgian horses might be due to excess glycogen production rather than issues with glycogen use or glucose uptake into muscle cells.
Insulin Sensitivity and PSSM
- The study aimed to find out if PSSM, a muscle disorder common in some breeds of horses, had an effect on insulin sensitivity, muscle fibers, and the activity of enzymes involved in the breakdown of glycogen (glycogenolytic) and glucose (glycolytic).
- The researchers used a method known as the hyperinsulinemic euglycemic clamp (HEC) technique to assess insulin sensitivity in 5 Belgians with PSSM and 5 without the condition. Insulin and glucose were administered intravenously and the levels of glucose and insulin in the blood were monitored throughout the process.
- The insulin sensitivity of horses with PSSM was compared with those without PSSM. The results showed that the disease did not significantly affect the whole-body insulin sensitivity of Belgian horses.
Enzyme Activity and Muscle Fibers
- The activity of glycogenolytic and glycolytic enzymes was also assessed in muscle biopsy samples from Belgians with and without PSSM. These enzymes are responsible for the breakdown of stored glycogen and glucose respectively in the body.
- Just like insulin sensitivity, the activities of these enzymes were also found to be similar in both groups of horses. This implies that PSSM does not affect their functioning.
- Further, the study went on to analyze the proportions of type 1, 2a, and 2b muscle fiber types in Belgians and compared them with those of 10 Quarter Horses. The results showed that Belgians, irrespective of their PSSM status, had a higher proportion of type 2a and a lower proportion of type 2b muscle fibers when compared to Quarter Horses.
Conclusion in Relation to PSSM
- Despite the variations in muscle fiber types, the study could not find any significant differences in insulin sensitivity or enzyme activities between Belgians with and without PSSM.
- The researchers concluded that PSSM in Belgians may not be due to impaired glycogen utilization or enhanced glucose uptake into muscle cells as previously thought. Rather, it may be attributable to excessive glycogen synthesis. This implies that the body might be making more glycogen than necessary which gets accumulated in the muscles leading to PSSM.
Cite This Article
APA
Firshman AM, Valberg SJ, Baird JD, Hunt L, DiMauro S.
(2008).
Insulin sensitivity in Belgian horses with polysaccharide storage myopathy.
Am J Vet Res, 69(6), 818-823.
https://doi.org/10.2460/ajvr.69.6.818 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA.
MeSH Terms
- Animals
- Biopsy / veterinary
- Blood Glucose / metabolism
- Female
- Glucose Clamp Technique / veterinary
- Glycogen Storage Disease / blood
- Glycogen Storage Disease / enzymology
- Glycogen Storage Disease / veterinary
- Histocytochemistry / veterinary
- Horse Diseases / blood
- Horses
- Insulin / blood
- Insulin Resistance / physiology
- L-Lactate Dehydrogenase / metabolism
- Male
- Muscle Fibers, Skeletal / metabolism
- Muscle, Skeletal / enzymology
- Muscle, Skeletal / metabolism
- Musculoskeletal Diseases / blood
- Musculoskeletal Diseases / enzymology
- Musculoskeletal Diseases / veterinary
- Phosphofructokinase-1, Muscle Type / metabolism
- Phosphoglucomutase / metabolism
- Phosphoglycerate Mutase / metabolism
- Phosphorylase a / metabolism
Citations
This article has been cited 5 times.- Lindåse S, Nostell K, Söder J, Bröjer J. Relationship Between β-cell Response and Insulin Sensitivity in Horses based on the Oral Sugar Test and the Euglycemic Hyperinsulinemic Clamp. J Vet Intern Med 2017 Sep;31(5):1541-1550.
- Lindåse S, Nostell K, Bröjer J. A modified oral sugar test for evaluation of insulin and glucose dynamics in horses. Acta Vet Scand 2016 Oct 20;58(Suppl 1):64.
- McCoy AM, Schaefer R, Petersen JL, Morrell PL, Slamka MA, Mickelson JR, Valberg SJ, McCue ME. Evidence of positive selection for a glycogen synthase (GYS1) mutation in domestic horse populations. J Hered 2014 Mar-Apr;105(2):163-72.
- Naylor RJ, Livesey L, Schumacher J, Henke N, Massey C, Brock KV, Fernandez-Fuente M, Piercy RJ. Allele copy number and underlying pathology are associated with subclinical severity in equine type 1 polysaccharide storage myopathy (PSSM1). PLoS One 2012;7(7):e42317.
- Vidal Moreno de Vega C, de Meeûs d'Argenteuil C, Boshuizen B, De Mare L, Gansemans Y, Van Nieuwerburgh F, Deforce D, Goethals K, De Spiegelaere W, Leybaert L, Verdegaal EJMM, Delesalle C. Baselining physiological parameters in three muscles across three equine breeds. What can we learn from the horse?. Front Physiol 2024;15:1291151.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
