Insulin is a hormone produced by the pancreas that plays a pivotal role in regulating glucose metabolism in horses. It facilitates the uptake of glucose by cells, thus maintaining blood sugar levels within a normal range. Insulin's function is integral to energy balance and metabolic processes in equines. Disruptions in insulin regulation can lead to metabolic disorders such as Equine Metabolic Syndrome (EMS), characterized by insulin resistance and associated with obesity and laminitis. This page aggregates peer-reviewed research studies and scholarly articles that explore the physiological role, regulatory mechanisms, and clinical implications of insulin in equine health and disease management.
Coffman JR, Colles CM.Sensitivity to insulin was assessed in ponies episodically affected with chronic laminitis by measurement of blood glucose and arterial blood pressure during insulin tolerance tests. In terms of blood glucose values, laminitic ponies were significantly less sensitive to insulin than controls. Conversely, a post-insulin decline in diastolic, systolic and mean blood pressure values was significantly greater in laminitic ponies than in controls.
Ross MW, Lowe JE, Cooper BJ, Reimers TJ, Froscher BA.A 12-year-old, 195 kg Shetland pony broodmare had eight seizures between May 29 and August 7, 1979. Plasma glucose levels during three of these seizures were markedly depressed (16, 18 and 19 mg/100 ml). Serum insulin levels were elevated during two of the seizures (86.0 and 97.7 microU/ml). Although a fasting hypoglycemia was not demonstrated, plasma glucose values during a normal day were abnormal; a plasma glucose level of 42 mg/100 ml was noted eight hours post-feeding. Serum insulin values obtained during an oral glucose tolerance test and intravenous glucagon tolerance test were consiste...
Rose RJ, Hodgson DR, Sampson D, Chan W.Plasma biochemical values were measured in 14 horses, before a 160 km endurance ride, immediately after 85 km, immediately after 160 km, after 30 min recovery period and the day after the ride. For statistical analysis, a group of 7 horses that completed the ride at a mean speed of 234 metres per min (m/min) (Fast Group) was compared with 7 horses that completed the ride at a mean speed of 144 m/min (Slow Group). Estimations were made of sodium, potassium, chloride, bicarbonate, glucose, creatinine, urea, bilirubin, iron, total protein, albumin, calcium, phosphate, cholesterol, alkaline phosph...
Ryder E, Ryder S.Venezuelan equine encephalitis (VEE) virus has been implicated as producing alterations in glucose metabolism in animals. We performed oral glucose tolerance tests and measured serum immunoreactive insulin responses in 13 patients who were infected by VEE virus during an epidemic in 1969, in Zulia State, Venezuela. No significant alterations in the glucose tolerance test were found. Sera of 86 diabetic outpatients and 98 control individuals with normal glycemia at a local hospital were tested for antibodies to VEE virus by hemagglutination inhibition. No statistically significant difference wa...
Thurmon JC, Neff-Davis C, Davis LE, Stoker RA, Benson GJ, Lock TF.The effects of intravenous xylazine (1.1 mg/kg) were studied in six thoroughbred horses (five mares and a stallion). Plasma glucose concentration increased to 168% of control at 45 min and decreased to 112% of control at 180 min. Insulin had decreased to 31% of control at 15 min. Thereafter, insulin concentration increased, reaching its highest concentration at 150 min. The mechanism for these changes is not fully understood and further investigation is indicated.
Hall GM, Adrian TE, Bloom SR, Lucke JN.Venous blood samples were collected before and immediately after an 80 km ride and a 42 km race. They were analysed for blood glucose and lactate, and for plasma non-esterified fatty acids, insulin, pancreatic glucagon, pancreatic polypeptide, gastrin, gastric inhibitory peptide, somatostatin and vasoactive intestinal polypeptide concentrations. The 80 km ride was associated with marked hypoglycaemia and a slight lactic acidaemia together with an increase in plasma glucagon, somatostatin, pancreatic polypeptide and vasoactive intestinal polypeptide values. The 42 km race produced hyperglycaemi...
Ralston SL, Baile CA.The hypothesis that changes in blood glucose concentrations and(or) utilization rate affect feeding behavior in ponies was tested. Ponies (n = 4) were fasted for 4 h, then given iv injections of 50% glucose [.2 g glucose/BW.75 kg (low dose, LD) or 1.0 g glucose/BW.75 kg (high dose, HD)] or an equal volume of normal saline (HDS; LDS) 5 min before being allowed access to pelleted feed. Blood samples were drawn at regular intervals pre- and post-treatment and analyzed for plasma glucose (PG), immunoreactive insulin (IRI) and glucagon concentrations. All glucose-treated animals immediately ate mea...
Gronwall R, Engelking LR.The effects of several treatments and their routes of administration on the reduction of hyperbilirubinemia in 9 pony mares after a 3-day fast were studied. Treatments were as follows: glucose given at doses of 1.2, 2.4, and 3.7 mg/min/kg of body weight; refeeding the base-line diet; feeding straw; and IV administration of taurocholic acid at a dosage of 0.07 mumol/min/kg. The 3 glucose dosages were each given by 3 different routes: IV, intraduodenal, and intragastric. The smallest dosage of glucose given by IV route reduced the plasma bilirubin concentration only 7%, even though other measure...
Rose RJ, Sampson D.Total and individual non-esterified fatty acids (NEFA), pyruvate, lactate, alpha ketoglutarate, acetoacetate, beta hydroxybutyrate, glucose and insulin were measured in horses during an 80 km endurance ride and during four days of food deprivation. In the latter group venous blood-gas and acid-base parameters, and plasma cortisol concentrations were also measured. During exercise and food deprivation the NEFA became considerably elevated, the predominant of which were oleic (35 per cent), palmitic (24 per cent), linoleic (19 per cent) and linolenic (10 per cent). By one hour after feeding tota...
Fowden AL, Ellis L, Rossdale PD.Plasma concentrations of insulin and glucose were measured in Pony and Thoroughbred foals at birth and at intervals thereafter for up to 7 days. The plasma concentrations of insulin in foals of both breeds at birth were 11.2 +/- 2.5 microU/ml (N = 6) and 13.5 +/- 1.5 microU/ml (N = 16) respectively. These values were similar to those obtained for foals in utero but were significantly less than those in adult animals. There was little variation in the plasma concentrations of insulin and glucose during the first 2 h of life and both concentrations tended to rise in the next 24-48 h. Although th...
Fessler JF, Bottoms GD, Roesel OF, Moore AB, Frauenfelder HC, Boon GD.A study was made of flunixin meglumine (FM), an analgesic agent with antiprostaglandin activity, in the management of endotoxin-induced changes in ponies. Three groups of 5 ponies each were used: A--controls, B--nontreated ponies with endotoxin-induced shock, and C--ponies with endotoxin-induced shock treated with FM. Shock was induced in anesthetized ponies with IV injections of Escherichia coli endotoxin. Disruption of glucose homeostasis, insulin levels, hemograms, aerobic metabolism, and cell damage as indicated by plasma enzymes were observed. Treatment with FM (5 minutes) after shock was...
Snow DH, Rose RJ.The alteration in plasma concentration of a number of hormones was investigated following an 80 km endurance ride. A marked rise in plasma cortisol levels occurred in all 17 animals investigated. Although decreased glucose levels did not occur in all animals, insulin levels fell in all horses examined. A high correlation (r = 0.89) was found between post ride glucose and plasma insulin concentrations. The plasma levels of both noradrenaline and adrenaline were significantly elevated post ride.
Doreau M, Martin-Rosset W, Barlet JP.Twenty-one circadian blood sample profiles were made in heavy brood mares during pregnancy, lactation or the dry, non-pregnant period. The mares were fed forage-rich diets containing different levels of energy and nitrogen (table 1). Each profile consisted of 7 samples taken at 8 a.m., 11 a.m., 3 p.m., 7 p.m., 11 p.m., 4 a.m. and 8 a.m. The animals were fed at 8:30 a.m. The eleven plasma components evaluated were glucose, non-esterified fatty acids, beta-hydroxybutyrate, acetate, alanine, insulin (energy metabolites), urea, total protein (nitrogen metabolites), calcium, inorganic phosphorus an...
Fowden AL, Barnes RJ, Comline RS, Silver M.Insulin secretion and the factors influencing beta-cell function were investigated in the chronically catheterized fetal foal and mare during the second half of gestation. The response of the fetal beta cells to exogenous glucose was also examined. The mean concentration of insulin in the fetal foal was 7.5 +/- 0.5 (S.E.M.) microunit./ml (n = 20) which was significantly less than the corresponding maternal value of 49.0 +/- 5.0 microunit./ml (n = 20, P < 0.01). The insulin concentration in non-pregnant horses was 24.5 +/- 1.5 microunit./ml (n = 5) which was significantly less than the value...
Lucke JN, Hall GN.Blood samples were taken before and immediately after 80 km and 40 km rides held on consecutive days and analysed for haematocrit, blood glucose and lactate, plasma sodium, potassium, calcium, albumin, free fatty acids (FFA), glycerol, bicarbonate, insulin, cortisol, glucagon, urea, creatinine, uric acid, bilirubin and alkaline phosphatase. Unusually hot weather probably contributed to haemoconcentration with a significant (P < 0.001) increase in haematocrit and plasma albumin. A fall in blood glucose, with a rise in FFA and glycerol were consistent with long distance riding and were associ...
Dybdal NO, Gribble D, Madigan JE, Stabenfelt GH.The effects of prolonged exercise on plasma concentrations of corticosteroids, insulin, glucose, lactate and beta-hydroxybutrate were studied in a group of horses competing in a 160 km endurance ride. Of the 53 horses included in the study at the outset, 23 completed the course. Plasma corticosteroids increased while glucose and insulin decreased during exercise. Little change occurred in plasma lactate or beta-hydroxybutyrate. The parameters studied did not result in the finding of any consistent significant differences beteeen individuals that completed and those that did not complete the co...
Matlina ESh, Bobylev IF, Skorupski K, Pukhova GS.The content of adrenaline, noradrenaline, ACTH, cortisol and insulin in the blood and excretion of catecholamines with urine were studied in horses after physical and emotional exposures. The highest degree of the sympathoadrenal system (SAS) and hypophysioadrenal system (HAS) activation followed by the insulin content decrease was observed after training. The known emotional exposure (the noise of hyppodrome) astivated both parts of SAS and HAS. The unknown emotional experience (electronic music) produced a strong adrenal medullar reaction. Analysis of the correlations showed that the initial...
Ralston SL, Van den Broek G, Baile CA.The feeding patterns of five pony geldings fed pelleted diets ad libitum were quantified for five 24-hr periods. Eighty percent of a given pony's total daily intake (6.3 ± .81 kg or 2.9 ± .41% BW) was eaten in 10 ± .9 separate meals. Each meal averaged .49 ±.13 kg of pellets and lasted 44 ± 10 minutes. The mean intermeal interval was 84 ± 10 min, with a maximum of 3 hour. The animals spent 38 ± 7.2% of a 24-hr period engaged in eating activities, 84 ± 3.7% of which was devoted to meals, the other 16% spent in nibbling activities. Forty-nine percent of the total daily intake was consume...
Ito S, Yamada Y, Hayashi M, Matsubara Y.Somatostatin-, glucagon- and insulin-containing cells in the rat and horse pancreatic islets were investigated by an indirect immunofluorescent technique using antibodies to insulin, glucagon and somatostatin. In the rat pancreatic islets, insulin-containing cells were located centrally, and glucagon and somatostatin or somatostatin-like substance (SLS)-containing cells were peripherally disposed and glucagon-containing cells were situated more peripherally as compared with distribution of somatostatin-containing cells. On the other hand, in the horse pancreatic islets, insulin-containing cell...
Kouider S, Kolb FE, Müller I, Pfüller C, Schneider J.Horses were examined for the behaviour of various blood constituents prior to and following infusions of solutions of glucose, fructose, invertose, and sorbitol. Infusion of 0.5 g/kg live weight glucose to six horses was followed by half-life variation between eleven and 23 minutes. Subsequent infusion of invertose to the same animals usually caused prolongation of glucose half-life. Half-life values were between 17 and 33 minutes for fructose and between 21 and 80 minutes for glucose. Infusion of 0.5 g/kg live weight fructose to two horses was followed by half-life values between 17 and 18 mi...
Helmstaedter V, Feurle GE, Forssmann WG.Equine pancreas was investigated with immunohistochemical methods to study the distribution of endocrine cells immunoreactive to anti-insulin, anti-glucagon, and anti-somatostatin. A-cells demonstrable by anti-glucagon are located in the center of Langerhans islets and frequently in the duct epithelium. Few A-cells are seen associated to acini. Anti-insulin reactive B-cells form a large zone around the center of the Langerhans islets in which some B-cells lie between exocrine cells and others, although few, are located in the duct epithelium. D-cells stained with anti-somatostatin serum form a...
Barnabé MA, Elliott J, Harris PA, Menzies-Gow NJ.Insulin dysregulation (ID) and hypoadiponectinaemia (total [adiponectin] <7.9 μg/mL) are risk factors for laminitis. They are sometimes, but not always, associated with obesity. Objective: To investigate the effects of pasture consumption and obesity on ID and circulating total [adiponectin] in ponies. Methods: Longitudinal. Methods: Seven native-breed ponies with normal basal and post-oral sugar test (OST) [insulin] and body condition score (BCS) 4.3-5.5/9 were allowed to graze until they reached BCS 7/9. Ponies were then maintained at BCS 7/9 until completion of the study (week 22). Morph...
Boshuizen B, De Maré L, Oosterlinck M, Van Immerseel F, Eeckhaut V, De Meeus C, Devisscher L, Vidal Moreno de Vega C, Willems M, De Oliveira JE....Aleurone, derived from the bran layer of grains like wheat and barley, has demonstrated positive effects on energy metabolism in pigs, mice, and untrained horses, influencing glucose-insulin dynamics and gut microbiome composition. Training itself enhances insulin sensitivity in horses, similar to the improvements in performance capacity observed in human athletes. This study aimed to investigate whether aleurone supplementation provides additional benefits to training by modulating insulin metabolism and gut microbiota in Standardbred mares. Unassigned: Sixteen Standardbred mares (aged 3-5 ye...
Hallman IAM, Raekallio MR, Karikoski NP.Vatinoxan is a peripherally acting alpha2-adrenoceptor antagonist used in veterinary medicine to attenuate the side effects of alpha2-adrenoceptor agonists. Vatinoxan also increases insulin response and reduces blood glucose (BG) after intravenous glucose in other species. The aim of this study was to investigate the effects of vatinoxan on BG and insulin concentration in horses after intravenous glucose. The design was an assessor-blind cross-over study. Nine horses were assigned to intravenous vatinoxan (0.2 mg/kg; VAT) or saline (SAL). Horses were administered an intravenous glucose bolus (...
McGuire CJ, Knowles EJ, Harris PA, Menzies-Gow NJ.Circulating insulin concentrations are used to quantify risk of laminitis in currently non-laminitic ponies. Basal serum activin A (AA) concentration has previously been positively correlated with serum insulin concentrations 60 minutes (T60) following an oral sugar test (OST) in ponies with equine metabolic syndrome. Therefore, circulating AA might be a useful marker for insulin dysregulation (ID) and laminitis risk. Objective: To explore the relationship between circulating AA concentrations at baseline (T0) and T60 in ponies that developed laminitis within six months and non-laminitic ponie...
Michanek P, Bröjer J, Lilliehöök I, Fjordbakk C, Erkas M, Löwgren M, Hedeland M, Bergquist J, Ekstrand C.Sodium-glucose co-transporter 2 inhibitors like canagliflozin (CFZ) have shown promise in preventing hyperinsulinemia-associated laminitis in horses, but data on pharmacokinetics, tolerability, and controlled studies are limited. This randomized, open-label, placebo-controlled, crossover study evaluated these aspects of CFZ treatment in eight healthy Standardbred mares. Each horse received single supratherapeutic oral doses of CFZ (1.8 mg/kg or 3.6 mg/kg) and placebo, with a two-week washout between treatments. A graded glucose infusion (GGI) was administered post-treatment to evaluate glu...
Ferreira C, Palhares MS, de Melo UP, Leme FOP, Maranhão RPA, Garcia HC, Gheller VA.Starvation and nutritional support clinically influence horses, particularly during the treatment of gastrointestinal diseases and post-surgical recovery. In this study, we aimed to evaluate the effects of different nutritional strategies on the endocrine response of horses subjected to exploratory laparotomy followed by food deprivation. Sixteen healthy adult horses were randomly allocated into four groups (n=4) based on treatments: enteral fluid therapy without (ENTFL) or with glutamine (ENTGL), and parenteral fluid therapy with glucose (PARFL) or total parenteral nutrition with glutamine (P...
Mlyneková E, Zaťko S, Halo M, Imrich I, Halo M.This study aimed to examine the seasonal dynamics of non-structural carbohydrates in pasture and their relationship to metabolic indicators in horses with a history of laminitis. Thirty Hucul mares were divided into a laminitis group (LG, = 15) and a control group (CG, = 15). Insulin, glucose, fructosamines concentrations and body weight were monitored during four sampling periods (S0-S3), while pasture variables were analyzed during three periods (S1-S3). The concentration of water-soluble carbohydrates was highest in May (126.8 g/kg DM) and measured lower in October (57.9 g/kg DM), while s...
Rollet M, Flyps J, Vernemmen I, van Loon G, Schauvliege S.Hyperkalaemia is an uncommon complication of general anaesthesia in healthy horses. This case report describes the occurrence of life-threatening acute hyperkalaemia in a 13-year-old, female French Trotter anaesthetised for experimental right and left atrial 3D electro-anatomical mapping. Intra-operative development of hyperkalaemia (7.55 mmol/L) (Ref. 3.00-4.00 mmol/L) with atrial standstill on ECG necessitated transvenous ventricular pacing while initial treatment with insulin and glucose was initiated. Plasma potassium levels continued to increase (8.00 mmol/L) prompting adjunctive tr...
Satué K, Fazio E, Velasco-Martínez MG, Barbiera G, La Fauci D.Growth hormone (GH) influences follicular development mainly by stimulating insulin-like growth factor 1 (IGF-1), which acts systemically and locally within the ovary. However, the metabolic profile of follicular fluid (FF) in mares, particularly markers such as fructosamine (FRUCT), an indicator of glucose metabolism, remains poorly characterized. This study aimed to evaluate GH, IGF-1, and FRUCT concentrations in plasma and FF and their variation across follicle sizes. Sixty ovaries were collected during the breeding season from 30 clinically normal mares raised for meat production. Blood sa...
Vasco ACCM, Warren LK, Silva GM, Cuervo-Vivas W, Brandi RA, Silva VP, Lance JM, Dubeux JC, Wickens CL.Rhizoma peanut (RP, Arachis glabrata Benth) is an alternative legume forage to alfalfa (ALF, Medicago sativa L.) with less non-structural carbohydrates and crude protein. Yet, metabolic responses to consuming RP hay have never been evaluated in horses. Objective: The objective of this study was to investigate the effect of feeding RP 'Florigraze' hay on fecal and blood metabolic variables compared to alfalfa 'Legendary XHD' and bermudagrass (BMG, Cynodon dactylon L. 'Coastal') hays fed to maintenance horses. Methods: Six mature Quarter Horse geldings (596±40 kg) were randomly assigned to one ...
Hallowell KL, van Eps AW, Kulp JC, Schnabel LV.Lipemia is a common comorbidity in horses with obesity or equine metabolic syndrome, but the impact of lipemia on the measurement of insulin and adiponectin has not been evaluated. Objective: To evaluate endogenous and exogenous lipemic interference with equine insulin and adiponectin measurements via several commercial assays. Methods: Endogenous lipemia was evaluated using plasma and serum samples with triglyceride concentrations of 1000 mg/dL (n = 6 each). Sample insulin concentrations were determined via fluorescence enzyme immunoassay (FEIA), ELISA, and lateral flow assay (LFA). ...
Teague P, Dark M, Verdugo D, Freeman D, McFarlane D.The equine pancreas remains understudied, particularly in the context of endocrine disease. This study aimed to characterize regional islet distribution and composition in the normal equine pancreas and investigate how hyperinsulinemia (HI) and pituitary pars intermedia dysfunction (PPID) influence pancreatic islet morphology and hormone expression. In the first experiment, pancreas samples from eight healthy horses were collected and analyzed across three anatomical locations: left lobe, body, and right lobe. The left lobe exhibited a greater relative islet area and perimeter compared to the ...
Viviani P, Ragno VM, Parker S, Montgomery JB.Endocrine disorders in horses, such as pituitary pars intermedia dysfunction and equine metabolic syndrome, rely on hormone testing for diagnosis, but seasonal and regional variabilities highlight the need for locally generated data. Objective: To characterize monthly blood concentrations of ACTH and insulin over 1 year in healthy horses in Saskatchewan. A secondary objective was to assess the association between these outcomes and the following factors: sex, age, breed, pregnancy status, level of exercise, body condition score, and cresty neck score. Methods: Sixty-eight clinically healthy, c...
Affonso FJ, Alonso MA, Bringel B, Douglas R, de Paula Nogueira G, Boakari YL, Fernandes CB.Glucose metabolism adapts to gestation, resulting in progressive physiological insulin resistance and increased insulin secretion to maintain maternal euglycemia and glucose availability for the developing fetus. These changes can impact mare fertility and maternal and neonatal health. This is the first comparison of body condition, regional adiposity, insulin and glucose dynamics, lipid metabolism, and cytokine production between lactating and non-lactating mares before, during pregnancy, and early postpartum. Twelve pregnancies from 9 broodmares, five nonlactating (NL) and seven lactating (L...
Bertin FR, van Eps AW, de Tonnerre DJ, Kulp JC, Stefanovski D.Dexamethasone is used to experimentally induce insulin resistance; however, its impact on insulin secretion is unclear. This study aimed to assess the responses to oral carbohydrate challenges in dexamethasone-treated horses. Unassigned: 8 healthy Standardbreds received 0.08 mg/kg of dexamethasone IM every 48 hours for 14 days in June 2022 (winter in the Southern hemisphere). Oral glucose tests (OGT) were conducted before treatment (day 1) and on days 8 and 15. Glucose, insulin, triglycerides, total and active glucagon-like peptide-1 (tGLP-1 and aGLP-1) and glucose-dependent insulinotropic pol...
Rey-Conejo R, Toribio RE, Möller S, Müller E, Fores-Jackson P.Insulin dysregulation is a key component of equine metabolic syndrome and is commonly assessed using basal insulin concentrations. Different analyzers may yield variable insulin results, limiting comparability. Objective: To assess the analytical performance of the ADVIA Centaur XPT chemiluminescent immunoassay (CLIA) for equine insulin measurement and to establish adapted decision thresholds based on comparison with a previously used CLIA method. Methods: Precision, linearity, and dilution recovery were assessed for the ADVIA Centaur XPT. A total of 89 equine serum samples submitted for basal...
Scoggin KE, Adlan F, Fedorka CE, Rakha SI, Stout TAE, Troedsson MHT, Ali HE.The insulin-like growth factor (IGF) system regulates implantation, placental development, and angiogenesis in eutherian mammals. However, little is known about the changes in this system in equine placenta (chorioallantois; CA) and the endometrium (EN) during pregnancy, or the relationship to vascular endothelial growth factor () expression. The current study investigated the expression of the IGF system components, namely the ligands ( and ), their receptors (, , and ), and their binding proteins ( and s) in equine CA at 45 days, 4, 6, 10, and 11 months of gestational age (GA) and immediatel...
Menzies-Gow NJ.Pituitary pars intermedia dysfunction (PPID) is a common, slowly progressive, neurodegenerative disorder of the older horse. Oxidative damage to the hypothalamic periventricular neurons results in loss of dopaminergic inhibition of the pars intermedia region of the pituitary gland. Consequently, there is increased production of the pro-opiomelanocortin (POMC)-derived hormones normally produced by this region, as well as initial melanocyte hypertrophy and hyperplasia, followed by adenomatous change. Clinical signs that are highly suggestive of the disease are generalised and regional hypertrich...
Thane K, Voth R, Klee R, Warnken T, Chukwu V, Frank N.Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are promising treatments to manage hyperinsulinemia in horses with insulin dysregulation (ID). Objective: The SGLT2i velagliflozin decreases insulin concentration in horses with ID. Methods: Privately-owned adult horses (n = 37) with laboratory-confirmed ID (low-dose oral sugar test insulin concentration > 75 μIU/mL). Methods: Double-blind randomized placebo-controlled trial. Horses received placebo (n = 19) or velagliflozin 0.3 mg/kg PO q24h (n = 18) for 20 weeks (Study Period 1, SP1) immediately followed by a 20-week ope...
Bourebaba N, Domagała J, Bourebaba L.Equine metabolic syndrome (EMS) is associated with chronic low-grade inflammation, disruptions in mitochondrial dynamics and function, and an increased risk of developing laminitis. Recent research has highlighted that reduced levels of sex hormone-binding globulin (SHBG) in the bloodstream are linked to higher susceptibility to obesity, insulin resistance, and diabetes, potentially contributing to broader metabolic imbalances. This study aimed to evaluate whether exogenously administered SHBG could protect adipose-derived stem cells from horses affected by EMS (EqASC) against mitochondrial dy...
Horses maintained under traditional management systems and dependent on natural forages are often exposed to seasonal and compositional variations that can affect metabolic homeostasis. This study examined associations between forage nutrient composition and metabolic-morphometric indicators in horses from four agroecologically distinct regions of northwestern Romania. Eighty-eight horses managed under semi-extensive rural conditions underwent clinical examination, body condition scoring (BCS), cresty neck scoring (CNS), and fasting blood sampling. Forage samples ( = 34) from daily rations wer...
Donnelly CG, Peng S, Pflieger L, Manfredi J, Coleman M, Rappaport N, Price ND, Finno CJ.Metabolic syndrome (MetS)-encompassing obesity, insulin resistance, dyslipidemia, and hypertension-is prevalent in both humans and horses, offering a unique opportunity to explore shared pathophysiological mechanisms across species in a controlled model organism. In this first report from the Pioneer 100 Horse Health Project (P100HHP), we conducted a longitudinal, multi-omic analysis of 108 deeply phenotyped horses to interrogate individual health trajectories for precision insights into MetS. We identified two primary metabotypes: one characterized by elevated unsaturated triglycerides (TGs) ...
Norton EM, Plumb S, Shane D, Smalley L, McKendry K, Scharf B, Zemel M.Supplements claiming to improve metabolic profiles in equine metabolic syndrome (EMS) often lack scientific validation. Objective: To evaluate the effect of a supplement containing leucine, resveratrol and pyridoxine on the metabolic profile in ponies with EMS. Methods: Unmasked randomised, placebo-controlled field trial. Methods: Thirty-eight ponies completed the trial across five farms. Ponies were age and sex matched per farm and randomly assigned to the supplement (n = 20) or placebo group (n = 18) with owners masked to group assignments. Ponies were sampled at days -1/0 (T1), 7/8 ...
Page AE, McPeek JL, Carattini S, McGreevy E, Adam E.The goal of this project was to examine the metabolic effects of IA methylprednisolone acetate (MPA) following injection into multiple low-motion joints. Unassigned: Six 3-year-old geldings without pituitary pars intermedia dysfunction or insulin dysregulation were randomly injected with 20 mg of IA MPA/joint (80 mg total; bilateral distal hock joints) or an equal volume of saline. Serial blood samples were collected for resting ACTH, cortisol, insulin, and glucose, as well as insulin and glucose following repeated low-dose oral sugar tests. Treatments were crossed over after a 6-week washout,...
Andrews KE, Sibthorpe PEM, Fitzgerald DM, de Laat MA.Equine insulin dysregulation (ID) is a common condition that predisposes to hyperinsulinaemia-associated laminitis. Improved pathophysiological understanding would enable better management of ID and reduce the risk of laminitis. The incretin peptides, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), augment the insulin response to dietary glucose and GLP-1 has been implicated in the pathophysiology of ID. However, their temporal variation in response to a low-energy diet has not been reported. This study determined the variation in GLP-1, GIP and insulin ...
Page AE, McPeek JL, McGreevy E, Carattini S, Adam EN.Intra-articular (IA) corticosteroids can cause hyperinsulinemia, which can subsequently increase the risk of laminitis, particularly in horses with insulin dysregulation (ID). Sodium glucose cotransporter 2 inhibitors (SGLT2i), a drug class that is being utilised more commonly in horses with insulin dysregulation, could potentially be used to control post-IA corticosteroid hyperinsulinemia. Objective: To determine whether treatment with the SGLT2i drug ertugliflozin decreases hyperinsulinemia following intra-articular corticosteroid administration in metabolically normal horses. Methods: Prosp...
Lowndes CR, Boyle AG, Kulp J, Stefanovski D, Davis JL, van Eps A.To characterize the effects of pioglitazone (2 mg/kg, PO, either q 24 h [PIO-SID] or q 12 h [PIO-BID]) in equids with severe hyperinsulinemia. Unassigned: 17 client-owned equids with severe resting hyperinsulinemia (> 100 µIU/mL) were assigned to PIO-SID or PIO-BID in a prospective cohort study with rolling enrollment over an 11-month study period (December 13, 2022, to November 17, 2023). Basal insulin, total and high-molecular-weight adiponectin concentrations, and plasma pioglitazone concentrations were measured over 70 days. Oral sugar tests (OSTs) were performed on days 0 and 28. Results...
Bourebaba L, Panek M, Piedra LCC, Bourebaba N.Fetuin-A (FetA) is a multifactorial glycoprotein primarily synthesized by the liver with additional expression in adipose tissue, the abundance of which is tightly regulated by the FBXW7 E3 ubiquitin ligase. Recently, FetA has been implicated in the pathogenesis of insulin resistance and associated metabolic failures in humans through its potent and selective inhibition of insulin receptor tyrosine kinase activity, however, no studies have yet directly investigated its role in the development and progression of equine obesity. In this investigation, FetA levels were measured in serum, liver, a...
Anger-Håål C, Fjordbakk CT, Ekstrand C, Skedsmo FS, Rørtveit R.Insulin dysregulation is a hallmark of equine metabolic syndrome (EMS), and in recent years, pharmacological treatment with sodium-dependent glucose transporter 2 inhibitors (SGLT2i) have shown promise in reducing the risk of hyperinsulinemia-associated laminitis in horses diagnosed with EMS. In humans and laboratory animals, this transporter protein is responsible for the majority of renal tubular glucose reabsorption, however, the presence of this and the related sodium-dependent glucose transporter 1 (SGLT1) have not yet been studied in equine kidneys. Additionally, studies in humans and la...
