Effects of short- and long-term recombinant equine growth hormone and short-term hydrocortisone administration on tissue sensitivity to insulin in horses.
Abstract: To determine the effects of short-term IV administration of hydrocortisone or equine growth hormone (eGH) or long-term IM administration of eGH to horses on tissue sensitivity to exogenous insulin. Methods: 5 Standardbreds and 4 Dutch Warmblood horses. Methods: The euglycemic-hyperinsulinemic clamp technique was used to examine sensitivity of peripheral tissues to exogenous insulin 24 hours after administration of a single dose of hydrocortisone (0.06 mg/kg), eGH (20 microg/kg), or saline (0.9% NaCl) solution and after long-term administration (11 to 15 days) of eGH to horses. The amounts of metabolized glucose (M) and plasma insulin concentration (I) were determined. Results: Values for M and the M-to-I ratio were significantly higher 24 hours after administration of a single dose of hydrocortisone than after single-dose administration of eGH or saline solution. After long-term administration of eGH, basal I concentration was increased and the mean M-to-I ratio was 22% lower, compared with values for horses treated with saline solution. Conclusions: Increases in M and the M-to-I ratio after a single dose of hydrocortisone imply that short-term hydrocortisone treatment increases glucose use by, and insulin sensitivity of, peripheral tissues. Assuming a single dose of hydrocortisone improves sensitivity of peripheral tissues to insulin, it may be an interesting candidate for use in reducing insulin resistance in peripheral tissues of horses with several disease states. In contrast, long-term administration of eGH decreased tissue sensitivity to exogenous insulin associated with hyperinsulinemia. Therefore, increased concentrations of growth hormone may contribute to insulin resistance in horses with various disease states.
Publication Date: 2005-12-13 PubMed ID: 16334949DOI: 10.2460/ajvr.2005.66.1907Google Scholar: Lookup
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- Journal Article
Summary
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The research article investigates the effects of various pharmaceutical substances on the insulin sensitivity in horses. The substances tested were short-term intravenous (IV) administration of hydrocortisone or equine growth hormone (eGH), and long-term intramuscular (IM) administration of eGH.
Methods of Research
- The study involved five Standardbreds and four Dutch Warmblood horses.
- Insulin sensitivity was examined using the euglycemic-hyperinsulinemic clamp technique, a method to measure the efficiency of insulin to lower blood glucose (blood sugar).
- Horses were administered with saline solution (0.9% NaCl), hydrocortisone (0.06 mg/kg), or eGH (20 microg/kg) and their reaction to insulin noted 24 hours after.
- Afterwards, some horses were also given eGH over a prolonged period of 11 to 15 days.
Findings
- The test results revealed that glucose metabolism (M) and the ratio of metabolized glucose and plasma insulin (M-to-I) were higher 24 hours after a single dose of hydrocortisone when compared to single-dose administration of eGH or saline solution.
- On the other hand, basal insulin concentration increased and the average M-to-I ratio fell by 22% after the long-term administration of eGH. These results were compared to the response observed in horses treated with a saline solution.
Interpretation and Conclusions
- An increase in M and the M-to-I ratio implies that single-dose administration of hydrocortisone enhances glucose utilization and insulin sensitivity in peripheral tissues. Consequently, hydrocortisone may be a therapeutic candidate to reduce insulin resistance in horses affected by various diseases.
- However, long-term administration of eGH was found to reduce tissue sensitivity to artificially administered insulin. This condition, known as hyperinsulinemia, indicates that excessive growth hormones could contribute to insulin resistance in horses suffering from different diseases.
Cite This Article
APA
de Graaf-Roelfsema E, Tharasanit T, van Dam KG, Keizer HA, van Breda E, Wijnberg ID, Stout TA, van der Kolk JH.
(2005).
Effects of short- and long-term recombinant equine growth hormone and short-term hydrocortisone administration on tissue sensitivity to insulin in horses.
Am J Vet Res, 66(11), 1907-1913.
https://doi.org/10.2460/ajvr.2005.66.1907 Publication
Researcher Affiliations
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
MeSH Terms
- 3-Hydroxybutyric Acid / blood
- Animals
- Blood Glucose / metabolism
- Cross-Over Studies
- Drug Interactions
- Fatty Acids, Nonesterified / blood
- Female
- Glucose Clamp Technique / veterinary
- Growth Hormone / pharmacology
- Horse Diseases / blood
- Horse Diseases / metabolism
- Horses / blood
- Horses / metabolism
- Hydrocortisone / pharmacology
- Insulin / pharmacology
- Insulin Resistance
- Insulin-Like Growth Factor I / metabolism
- Male
- Random Allocation
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