Physiologic assessment of blood glucose homeostasis via combined intravenous glucose and insulin testing in horses.
Abstract: To characterize the physiologic response to i.v. bolus injection of glucose and insulin for development of a combined glucose-insulin test (CGIT) in horses. Methods: 6 healthy mares and 1 mare each with pituitary adenoma and urolithiasis. Methods: Horses were given a CGIT (glucose, 150 mg/kg; insulin, 0.1 U/kg); results were compared with a singular i.v. glucose tolerance test (GTT; 150 mg/kg) and a singular i.v. insulin sensitivity test (IST; 0.1 U/kg). Healthy horses were also given a CGIT after receiving xylazine and undergoing stress. Results: Physiologically, the CGIT resulted in a 2-phase curve with positive (hyperglycemic) and negative (hypoglycemic) portions; the positive phase came first (250% of baseline at 1 minute). The descending segment declined linearly to baseline by approximately 30 minutes and to a nadir at 58% of baseline by 75 minutes. After a 35-minute valley, a linear ascent to baseline began. Addition of insulin in the CGIT increased glucose utilization by approximately 4.5 times during the positive phase but not during the negative phase. The diseases' effects and experimental inhibition of insulin secretion with xylazine and stress were detectable by use of the 2 phases of the CGIT. Only a single positive phase resulted from the GTT and a single negative phase from the IST CONCLUSIONS AND CLINICAL RELEVANCE: The CGIT resulted in a consistent, well-defined glycemia profile, which can be disrupted experimentally or by a disease process. The CGIT has clinical potential because it provides integrated information and more information than either the singular GTT or IST.
Publication Date: 2005-11-03 PubMed ID: 16261835DOI: 10.2460/ajvr.2005.66.1598Google 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.
- Comparative Study
- Journal Article
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.
The research delved into how the physiological response in horses to the combined injection of insulin and glucose can be studied for the development of a blood glucose homeostasis assessment tool. By testing the reactions in healthy horses as well as those with certain illnesses, researchers were able to deduce that the Combined Glucose-Insulin Test (CGIT) provides a comprehensive profile of glucose metabolism and utilization.
Methods
For the experiment, the researchers gathered a test group which consisted of:
- Six healthy mares
- One mare with a pituitary adenoma
- One mare suffering from urolithiasis (the formation of stones in the bladder or urinary tract)
The horses were given a CGIT with specific doses of insulin and glucose and the effects and changes were studied. These results were then compared to a singular Intravenous Glucose Tolerance Test (GTT) and a singular Intravenous Insulin Sensitivity Test (IST).
Additionally, CGITs were performed on healthy horses that were under stress or under the influence of xylazine, a relaxant and analgesic.
Results
The CGIT resulted in a two-phase curve. The first phase was a positive or hyperglycemic phase, causing an immediate spike in blood glucose levels (around 250% of the baseline at 1 minute). This was followed by a descending segment that declined linearly back to baseline values.
The addition of insulin in the CGIT significantly increased glucose utilization during the positive phase, although not during the negative phase. By using the two phases, researchers were able to detect the effects of specific diseases and the inhibition of insulin secretion due to xylazine or stress.
Conclusions and Clinical Relevance
The repercussions stemming from this research indicated that the CGIT consistently produced a distinct profile of blood glucose levels. Disruptions to this profile by disease or experimental manipulation were identifiable thus underlining the CGIT’s clinical potential.
Furthermore, the CGIT provided more holistic and integrated information compared to either the singular GTT or IST, making it a potentially more effective tool for understanding and assessing blood glucose homeostasis in horses.
Cite This Article
APA
Eiler H, Frank N, Andrews FM, Oliver JW, Fecteau KA.
(2005).
Physiologic assessment of blood glucose homeostasis via combined intravenous glucose and insulin testing in horses.
Am J Vet Res, 66(9), 1598-1604.
https://doi.org/10.2460/ajvr.2005.66.1598 Publication
Researcher Affiliations
- Department of Comparative Medicine, Physiology Section, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
MeSH Terms
- Animals
- Blood Glucose / drug effects
- Blood Glucose / physiology
- Diabetes Mellitus / diagnosis
- Diabetes Mellitus / veterinary
- Diagnostic Techniques, Endocrine / veterinary
- Evaluation Studies as Topic
- Glucose / administration & dosage
- Glucose / pharmacology
- Homeostasis / physiology
- Horse Diseases / diagnosis
- Horses
- Insulin / administration & dosage
- Insulin / pharmacology
- Time Factors
Citations
This article has been cited 24 times.- Galinelli NC, Bamford NJ, Erdody ML, Mackenzie SA, Warnken T, Harris PA, Sillence MN, Bailey SR. Effect of pergolide treatment on insulin dysregulation in horses and ponies with pituitary pars intermedia dysfunction. Equine Vet J 2025 Nov;57(6):1612-1622.
- Loos CMM, Zhao S, Li L, Li J, Han W, Vanzant ES, McLeod KR. Essential oil supplementation improves insulin sensitivity and modulates the plasma metabolome of hyperinsulinemic horses. Front Vet Sci 2024;11:1444581.
- Loos C, Castelein A, Vanzant E, Adam E, McLeod KR. Nutraceutical Supplement Mitigates Insulin Resistance in Horses with a History of Insulin Dysregulation During a Challenge with a High-Starch Diet. Animals (Basel) 2024 Nov 25;14(23).
- Stoeckle SD, Timmermann D, Merle R, Gehlen H. Plasma Amino Acid Concentration in Obese Horses with/without Insulin Dysregulation and Laminitis. Animals (Basel) 2022 Dec 18;12(24).
- Loos CMM, Urschel KL, Vanzant ES, Oberhaus EL, Bohannan AD, Klotz JL, McLeod KR. Effects of Bromocriptine on Glucose and Insulin Dynamics in Normal and Insulin Dysregulated Horses. Front Vet Sci 2022;9:889888.
- Timko KJ, Hostnik LD, Watts MR, Chen C, Bercz A, Toribio RE, Belknap JK, Burns TA. Diagnostic evaluation of insulin and glucose dynamics in light-breed horses receiving dexamethasone. Can Vet J 2022 Jun;63(6):617-626.
- Gehlen H, Schwarz B, Bartmann C, Gernhardt J, Stöckle SD. Pituitary Pars Intermedia Dysfunction and Metabolic Syndrome in Donkeys. Animals (Basel) 2020 Dec 8;10(12).
- Blaue D, Schedlbauer C, Starzonek J, Gittel C, Brehm W, Blüher M, Pfeffer M, Vervuert I. The influence of equine body weight gain on inflammatory cytokine expressions of adipose tissue in response to endotoxin challenge. Acta Vet Scand 2020 Apr 22;62(1):17.
- Langner K, Blaue D, Schedlbauer C, Starzonek J, Julliand V, Vervuert I. Changes in the faecal microbiota of horses and ponies during a two-year body weight gain programme. PLoS One 2020;15(3):e0230015.
- Kritchevsky JE, Muir GS, Leschke DHZ, Hodgson JK, Hess EK, Bertin FR. Blood glucose and insulin concentrations after alpha-2-agonists administration in horses with and without insulin dysregulation. J Vet Intern Med 2020 Mar;34(2):902-908.
- Hodge E, Kowalski A, Torcivia C, Lindborg S, Stefanovski D, Hart K, Frank N, van Eps A. Effect of thyrotropin-releasing hormone stimulation testing on the oral sugar test in horses when performed as a combined protocol. J Vet Intern Med 2019 Sep;33(5):2272-2279.
- Schedlbauer C, Blaue D, Gericke M, Blüher M, Starzonek J, Gittel C, Brehm W, Vervuert I. Impact of body weight gain on hepatic metabolism and hepatic inflammatory cytokines in comparison of Shetland pony geldings and Warmblood horse geldings. PeerJ 2019;7:e7069.
- Moser K, Banse H. Comparison of the glucose and insulin responses of horses to 2 formulations of corn syrup. Can Vet J 2019 Jun;60(6):637-643.
- Adolph S, Schedlbauer C, Blaue D, Schöniger A, Gittel C, Brehm W, Fuhrmann H, Vervuert I. Lipid classes in adipose tissues and liver differ between Shetland ponies and Warmblood horses. PLoS One 2019;14(3):e0207568.
- Meier A, de Laat M, Reiche D, Fitzgerald D, Sillence M. The efficacy and safety of velagliflozin over 16 weeks as a treatment for insulin dysregulation in ponies. BMC Vet Res 2019 Feb 26;15(1):65.
- Durham AE, Frank N, McGowan CM, Menzies-Gow NJ, Roelfsema E, Vervuert I, Feige K, Fey K. ECEIM consensus statement on equine metabolic syndrome. J Vet Intern Med 2019 Mar;33(2):335-349.
- Carslake HB, Pinchbeck GL, McGowan CM. Evaluation of a Chemiluminescent Immunoassay for Measurement of Equine Insulin. J Vet Intern Med 2017 Mar;31(2):568-574.
- Warnken T, Huber K, Feige K. Comparison of three different methods for the quantification of equine insulin. BMC Vet Res 2016 Sep 9;12(1):196.
- Bertin FR, Taylor SD, Bianco AW, Sojka-Kritchevsky JE. The Effect of Fasting Duration on Baseline Blood Glucose Concentration, Blood Insulin Concentration, Glucose/Insulin Ratio, Oral Sugar Test, and Insulin Response Test Results in Horses. J Vet Intern Med 2016 Sep;30(5):1726-1731.
- Dunbar LK, Mielnicki KA, Dembek KA, Toribio RE, Burns TA. Evaluation of Four Diagnostic Tests for Insulin Dysregulation in Adult Light-Breed Horses. J Vet Intern Med 2016 May;30(3):885-91.
- Morgan R, Keen J, McGowan C. Equine metabolic syndrome. Vet Rec 2015 Aug 15;177(7):173-9.
- Johnson PJ, Wiedmeyer CE, LaCarrubba A, Ganjam VK, Messer NT 4th. Diabetes, insulin resistance, and metabolic syndrome in horses. J Diabetes Sci Technol 2012 May 1;6(3):534-40.
- Söder J, Bröjer JT, Nostell KE. Interday variation and effect of transportation on indirect blood pressure measurements, plasma endothelin-1 and serum cortisol in Standardbred and Icelandic horses. Acta Vet Scand 2012 Jun 10;54(1):37.
- Johnson PJ, Wiedmeyer CE, Messer NT, Ganjam VK. Medical implications of obesity in horses--lessons for human obesity. J Diabetes Sci Technol 2009 Jan;3(1):163-74.
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
