Equine metabolism encompasses the biochemical processes that occur within horses to maintain life, including the conversion of food into energy, the synthesis of necessary compounds, and the elimination of waste products. These processes are essential for supporting various physiological functions such as growth, reproduction, and physical performance. Key components of equine metabolism include carbohydrate, fat, and protein metabolism, each of which contributes to the overall energy balance and health of the horse. Factors influencing metabolic rate and efficiency in horses include age, breed, diet, exercise, and health status. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of metabolic processes in equine physiology.
Waller AP, Geor RJ, Spriet LL, Heigenhauser GJ, Lindinger MI.Oral acetate supplementation enhances glycogen synthesis in some mammals. However, while acetate is a significant energy source for skeletal muscle at rest in horses, its effects on glycogen resynthesis are unknown. We hypothesized that administration of an oral sodium acetate-acetic acid solution with a typical grain and hay meal after glycogen-depleting exercise would result in a rapid appearance of acetate in blood with rapid uptake by skeletal muscle. It was further hypothesized that acetate taken up by muscle would be converted to acetyl CoA (and acetylcarnitine), which would be metaboliz...
Hustace JL, Firshman AM, Mata JE.To determine pharmacokinetics and oral bioavailability of metformin in healthy horses. Methods: 4 adult horses. Methods: 6 g of metformin was administered 3 times IV and PO (fed and unfed) to each horse, by use of a crossover design, with a 1-week washout period between treatments. Plasma metformin concentration was determined via high-pressure liquid chromatography. Results: Mean +/- SD distribution half-life of metformin following IV administration was 24.9 +/- 0.4 minutes with a volume of distribution of 0.3 +/- 0.1 L/kg. Mean area under the curve was 20.9 +/- 2.0 h.microg/mL for IV adminis...
Patan B, Budras KD, Licka TF.To establish an ex vivo model of blood perfusion in the distal portion of isolated equine forelimbs that closely represents the in vivo situation in the laminar tissue of the hoof. Methods: 18 forelimbs collected from 9 healthy adult horses following slaughter at a licensed abattoir. Methods: The distal portion of isolated equine forelimbs from 9 horses were perfused under physiologic conditions over a period of 6, 8, and 10 hours with autologous blood. To determine cell viability in perfused tissues, indicators for metabolism (lactate generation and glucose and oxygen consumption) as well as ...
Kalck KA, Frank N, Elliott SB, Boston RC.To ascertain whether laminitis can be induced via administration of oligofructose (OF) at doses of 5.0 and 7.5 g/kg in horses and to assess glucose and insulin dynamics before and after treatment. Methods: 19 adult horses. Methods: Horses were fed OF (1.0 g/kg) mixed with oats for 6 days. Oligofructose at doses of 5.0 and 7.5 g/kg was then mixed with 4 L of water and administered (0 hours) to 8 (group A) and 4 (group B) horses, respectively, via nasogastric intubation; 8 horses received water alone. One horse in group A that did not develop laminitis was subsequently treated again and included...
Mosing M, Kuemmerle JM, Dadak A, Moens YP.A case of a pony with severe cyanide intoxication as a result of cherry ingestion is presented. General anaesthesia was performed for colic surgery. Severe metabolic lactate acidosis in combination with a high arterial oxygen partial pressure and clinically good peripheral perfusion parameters were the remarkable signs during anaesthesia. Severe hypothermia was obvious during recovery. Ten hours post-surgery the pony was euthanized as a result of neurological signs. The diagnosis of cyanide intoxication was made post-mortem. Conclusions: Cherry ingestion can lead to lethal cyanide intoxication...
Manso Filho HC, McKeever KH, Gordon ME, Manso HE, Lagakos WS, Wu G, Watford M.Glutamine is concentrated within skeletal muscle, where it has been proposed to play a regulatory role in maintaining protein homeostasis. The work presented here addressed the hypothesis that glutamine would be the most abundant free alpha-AA in plasma and skeletal muscle in the foal during the first year of life. Glycine, however, was the most abundant free alpha-AA in plasma at birth and between 3 and 12 mo of age. The concentration of glutamine, the second most abundant AA at birth, increased through the first 7 d (P < 0.05) and then returned to values similar to those at birth. This re...
Piccione G, Assenza A, Borruso M, Fazio F, Caola G.In the sport field, non-esterified fatty acids (NEFA) are important for the physical performance during the aerobic exercise of short intensity and long duration. In man, rat, goat and in the sedentary horse studies on the chronometabolism showed the presence of a circadian rhythm of the plasmatic concentration of NEFA while data for the athletic horse are lacking. To define a chronogram helpful for a specific planning and the differentiation of the training programmme in the athletic horse, the circadian pattern of some fatty acids (NEFA, palmitic, stearic, oleic, linoleic and linolenic acids...
Sasaki N, Tsuzuki N, Yamada M, Minami T, Yamada H.This study aimed to establish a standard dose and sample collection time for (13)C phenylalanine and (13)C-Dipeptide breath test in horses. To evaluate dose-dependent effects, healthy horses received 2.5 mg/kg, 5 mg/kg, and 10 mg/kg (13)C phenylalanine dissolved in 1 ml/kg distilled water and 1.25 mg/kg, 2.5 mg/kg, and 5 mg/kg (13)C dipeptide dissolved in 2 ml/ kg distilled water. Tmax was observed during the sample collection time. For (13)C phenylalanine, the standard deviation of Cmax at 5 mg/kg was lower than that of 10 mg/kg. For (13)C dipeptide, the standard deviation of Tmax was the low...
Ishii M, Kobayashi S, Acosta TJ, Miki W, Matsui M, Yamanoi T, Miyake Y, Miyamoto A.The aim of this study was to establish the effectiveness of administration of oxytocin (OT) on placental expulsion after foaling. Four foaling mares with the placentas retained for up 1 hr after foaling received OT (50 IU) administration at 1 hr intervals before expulsion of the placenta. The changes in the plasma concentrations of OT and the PGF2alpha metabolite (PGFM) were investigated, and the influence of OT administration was considered. The results were as follows. The placenta was expelled after one to three OT administrations in all four mares that received OT. In two mares, which expe...
Radin MJ, Sharkey LC, Holycross BJ.In addition to its role as an energy storage depot, adipose tissue is now recognized as a complex endocrine organ. Adipose tissue releases a variety of factors, termed adipokines, that regulate energy metabolism, cardiovascular function, reproductive status, and immune function. Some of the better-studied adipokines include leptin, adiponectin, and components of the renin-angiotensin system such as angiotensinogen. The function of more recently discovered adipokines such as resistin are under intense scrutiny. Abnormal production or regulation of adipokines occurs in obese individuals and is i...
Janiak M, Suska M, Dudzińska W, Skotnicka E.The aim of this study was to evaluate response of blood glutathione status and activity of glutathione-metabolizing antioxidant enzymes in erythrocytes of young trotters in basic training. Nine untrained trotters (aged 16-20 months) were exposed to a 4-month training program based on exercises at low-to-moderate intensity. The conditioning consisted of breaking the horses and running them on distances varying from 4 to 40 km a week. The workloads were increased on a 3-week basis. Exercise intensity was monitored by measuring heart rate and blood lactate. Blood samples were collected at rest, b...
Van Weyenberg S, Buyse J, Janssens GP.In this study 0 or 4 g of l-carnitine was supplemented for 7 days in a cross-over design of six healthy ponies to modulate glucose metabolism and leptin production. At the end of each period, serial blood samples were taken to measure glucose and insulin response, leptin, triglyceride (TG), non-esterified fatty acids (NEFA) and creatine phosphokinase. l-carnitine supplementation was associated with a decrease in postprandial plasma glucose and insulin concentration, indicating an enhanced glucose tolerance. In contrast, postprandial plasma leptin concentration was increased when l-carnitine wa...
Hackl S, van den Hoven R, Zickl M, Spona J, Zentek J.The aim of this study was to investigate the effect of short intense exercise on plasma amino acid concentrations in trotters and to test the repeatability of plasma amino acids concentration in samples obtained on two independent days under field conditions. Plasma amino acid concentrations were analysed in blood samples of 36 standardbred trotters before and after intense exercise over a distance of 2000 m. Sampling was repeated in 20 horses after 35 days. Exercise intensity was estimated from post-exercise lactate levels. Horses were divided in two groups according to a cut-off lactate conc...
Harris P, Geor RJ.The feeding of "low carbohydrate" or "low glycemic" diets has been recommended for management of horses with metabolic and endocrine disorders in which insulin resistance is a component. A "low carbohydrate" diet is a misnomer, however, because horses require that a significant proportion of their daily ration comprises structural carbohydrates (fiber/forage) to maintain gut health and mental wellbeing. This article provides a detailed description of the different carbohydrates in equine feeds. It also reviews the terminology used to describe glucose and insulin responses to the ingestion of c...
Harris P.This article reviews the principles of feeding management for endurance horses. The amount and type of dietary energy (calories) are key considerations in dietary management, because (1) there is evidence that the body condition score, an indicator of overall energy balance, influences endurance exercise performance, and (2) the source of dietary energy (ie, carbohydrate versus fat calories) impacts health, metabolism, and athletic performance. Optimal performance is also dependent on provision of adequate feed, water, and electrolytes on race day.
Tevell Aberg A, Olsson C, Bondesson U, Hedeland M.This paper describes a study where the metabolism of the non-steroidal anti-inflammatory drug meloxicam was investigated in six horses and in the filamentous fungus Cunninghamella elegans. The metabolites identified were compared between the species, and then the fungus was used to produce larger amounts of the metabolites for future use as reference material. C. elegans proved to be a good model of phase I meloxicam metabolism in horses since all four metabolites found were the same in both species. Apart from the two main metabolites, 5'-hydroxymethylmeloxicam and 5'-carboxymeloxicam, a seco...
Marañón G, Manley W, Cayado P, García C, de la Muela MS, Vara E.Colic could be accompanied by changes in the morphology and physiology of organs and tissues, such as the intestine. This process might be, at least in part, due to the accumulation of oxidative damage induced by reactive oxygen (ROS) and reactive nitrogen species (RNS), secondary to intestinal ischemia. Glutathione (GSH), being the major intracellular thiol, provides protection against oxidative injury. The aim of this study was to investigate whether ischemia-induced intestinal injury could be related with alterations in GSH metabolism. Results: Ischemia induced a significant increase in lip...
Duehlmeier R, Hacker A, Widdel-Bigdely A, von Engelhardt W, Sallmann HP.Glucose homeostasis depends on insulin-regulated glucose uptake in the skeletal muscles and fat tissues via glucose transporter (GLUT) 4 translocation into cellular plasma membranes. The present study sought to elucidate GLUT4 expression, GLUT1 and GLUT4 translocation and glucose uptake in the skeletal muscles of Shetland ponies. Semitendinosus muscle explants were removed by open muscle biopsy from six Shetland pony geldings under general anaesthesia. The expression of GLUT4 was analysed by measuring muscle crude membrane (CM) GLUT4 protein contents. To determine the insulin-stimulated GLUT t...
Edner AH, Essén-Gustavsson B, Nyman GC.Muscle metabolism in horses has been studied mainly by analysis of substances in blood or plasma and muscle biopsy specimens. By using microdialysis, real-time monitoring of the metabolic events in local tissue with a minimum of trauma is possible. There is limited information about muscle metabolism in the early recovery period after anaesthesia in horses and especially in the colic horse. The aims were to evaluate the microdialysis technique as a complement to plasma analysis and to study the concentration changes in lactate, pyruvate, glucose, glycerol, and urea during anaesthesia and in th...
Reijerkerk EP, Visser EK, van Reenen CG, van der Kolk JH.To compare the effects of IV administration of various doses of ovine corticotrophin-releasing hormone (oCRH) on plasma and saliva cortisol concentrations in healthy horses and determine whether an oCRH challenge test protocol is valid for use in adult horses. Methods: 24 healthy Warmblood horses. PROCEDURES-Each horse received oCRH in saline (0.9% NaCl) via IV administration at a dose of 0 (control treatment), 0.01, 0.1, or 1.0 Mg/kg (6 horses/group). Jugular blood and saliva samples were collected simultaneously 15 minutes before and immediately prior to injection (baseline); data from these...
Ho EN, Leung DK, Leung GN, Wan TS, Wong AS, Wong CH, Soma LR, Rudy JA, Uboh C, Sams R.Administration studies of levamisole in horses were carried out using two different levamisole preparations, namely, levamisole hydrochloride oral bolus and levamisole phosphate injectable solution. These preparations were analysed in detail for the presence of aminorex-like impurities. Both levamisole preparations were found to contain 1-(2-mercaptoethyl)-4-phenyl-2-imidazolidinone (I) and 4-phenyl-2-imidazolidinone (II) as degradation impurities, but neither aminorex nor rexamino was detected in these preparations. After the administration of these preparations to horses, aminorex, rexamino,...
DiMaio Knych HK, DeStefano Shields C, Buckpitt AR, Stanley SD.Substantial gaps exist in our knowledge of the metabolic clearance of therapeutic agents in horses. Accordingly, a cytochrome P450 monooxygenase in the 2C family was cloned from an equine liver, sequenced and expressed in a baculovirus expression system. Catalytic activities of the recombinant protein were measured with a number of substrates. The protein, assigned CYP2C92, displayed optimal catalytic activity with diclofenac using molar ratios of CYP2C92 to NADPH CYP450 reductase of 1:18. Addition of cytochrome b(5) to diclofenac incubations had no significant effect on metabolic turnover. CY...
Vervuert I, Klein S, Coenen M.The aim of this study was to investigate the effects of fat supplementation on postprandial glycaemic and insulinaemic responses in horses fed a corn meal. Four horses were fed three different diets: (1) cracked corn (CC), (2) cracked corn with soybean oil (CC+SBO), and (3) cracked corn with fish oil (CC+FO). Each diet was adjusted so there was a starch intake of 2 g/kg bodyweight (BW) and an intake of 0.2 mL/kg BW of FO and SBO. The increases in mean plasma glucose and insulin concentrations, peak values, and areas under the curve were similar for all diets (time P<0.05, diet not significa...
Ousey JC, Fowden AL, Wilsher S, Allen WR.Chronic and acute alterations in maternal nutrient intake during pregnancy alter pancreatic and hypothalamo-pituitary-adrenal (HPA) axis function in the offspring, before and after birth. Little is known about these effects. Objective: To determine whether maternal nutrient restriction caused by natural infection with Streptococcus equi altered endocrine function in neonatal foals born from mares fed a maintenance or high plane of nutrition throughout pregnancy. Methods: Ten primiparous mares received either a diet to maintain moderate body condition score (Moderate, n = 5) or a near ad libitu...
Piccione G, Giannetto C, Assenza A, Casella S, Caola G.We examined the response to exercise of selected physiological variables in horses performing the identical routine for eight days, in the morning (a.m.) or in the afternoon (p.m.). Heart rate (HR), systolic and diastolic blood pressure (BP), and body temperature (BT) were all consistently greater in the p.m. For BP and BT, the absolute increase above the a.m. values was the same at rest and during exercise. For HR, the absolute increase was greater during exercise, but the percent increase was the same as during rest. During exercise, blood glucose decreased, while blood lactate and skin temp...
Inoue Y, Matsui A, Asai Y, Aoki F, Yoshimoto K, Matsui T, Yano H.We studied the response of biochemical markers of bone metabolism to exercise intensity in horses. Four horses were walked on a mechanical walker for one week (pre-exercise). Then they performed low-speed exercise on a high-speed treadmill in the first week and medium-speed exercise in the second week and high-speed exercise in the third week of training. We measured two indices of bone resorption, serum hydroxyproline concentration and the urinary deoxypyridinoline/creatinine ratio, and serum osteocalcin (OC) concentration as an index of bone formation. Both indices of bone resorption gradual...
Rourke KM, Kohn CW, Levine AL, Rosol TJ, Toribio RE.Calcium has important physiological functions, and disorders of calcium homeostasis are frequent in horses. We have made important progress understanding equine calcium homeostasis; however, limited information on equine calcitonin (CT) is available, in part because of the lack of validated CT assays. To determine the CT response to high ionized calcium (Ca(2+)) concentrations in healthy horses, we induced hypercalcemia in 10 healthy horses using a calcium gluconate 23% solution (5mg/kg; 120 mL/500 kg horse) infused over 4 min. Four horses were infused with 120 mL of 0.9% NaCl and used as cont...
Calatroni A, Avenoso A, Ferlazzo AM, Lindner A, Campo GM.Plasma glycosaminoglycans (GAGs) were isolated and purified by chromatographic procedures in healthy humans and horses before and after physical exercise. A weak anion exchange resin was used to separate polyanions. Humans exercised on a cycloergometer, while horses were exercised on a treadmill and in show jumping competition. Some GAGs were isolated from untreated plasma and operationally defined as native proteoglycans (PGs), while the total GAG amount was isolated from mild alkali treated plasma. Plasma GAG concentrations in terms of galactosamine and galactose, the respective components o...
De Leo M, Giorgi M, Saccomanni G, Manera C, Braca A.Tramadol is a centrally acting analgesic drug that has been used clinically for the last two decades to treat pain in humans. The clinical response of tramadol is strictly correlated to its metabolism, because of the different analgesic activity of its metabolites. O-Desmethyltramadol (M1), its major active metabolite, is 200 times more potent at the micro-receptor than the parent drug. In recent years tramadol has been widely introduced in veterinary medicine but its use has been questioned in some species. The aim of the present study was to develop a new sensible method to detect the whole ...
Alvarado TD, Elghandour MMMY, Ekanem NJ, Alcala-Canto Y, Velázquez AE, Pacheco EBF, Purba RAP, Salem AZM.The present study was conducted to investigate the aqueous extracts of Azadirachta indica (AZN), Cnidoscolus angustidens (CNA), and their combination (MIX) at dosages of 0-, 0.6-, 1.2-, and 1.8- mL for their ability to reduce greenhouse gases and fermentation profiles in an in vitro study using horse feces and a nutrient-dense diet (as substrate). The quantity of greenhouse gas and fermentation profiles were determined in in vitro incubation for 48 h. Extracts of AZN, CNA, and MIX reduced total gas production of the incubated and degraded substrates in a dose-dependent and time-dependent manne...
Szydlarska J, Weiss C, Marycz K.Methyl-β-cyclodextrin (MβCD) is a cyclic oligosaccharide, commonly used as a pharmacological agent to deplete membrane cholesterol. In this study, we examined the effect of MβCD on adipose-derived mesenchymal stromal cells (ASCs) isolated form healthy horses (ASC) and from horses suffering from metabolic syndrome (ASC). We investigated the changes in the mRNA levels of the glucose transporter 4 (GLUT4) and found that MβCD application may lead to a significant improvement in glucose transport in ASC. We also showed that MβCD treatment affected GLUT4 upregulation in an insulin-independent m...
McCutcheon LJ, Geor RJ.Sweating responses were examined in five horses during a standardized exercise test (SET) in hot conditions (32-34 degrees C, 45-55% relative humidity) during 8 wk of exercise training (5 days/wk) in moderate conditions (19-21 degrees C, 45-55% relative humidity). SETs consisting of 7 km at 50% maximal O(2) consumption, determined 1 wk before training day (TD) 0, were completed on a treadmill set at a 6 degrees incline on TD0, 14, 28, 42, and 56. Mean maximal O(2) consumption, measured 2 days before each SET, increased 19% [TD0 to 42: 135 +/- 5 (SE) to 161 +/- 4 ml. kg(-1). min(-1)]. Peak swea...
Reeta Pösö A, Hyyppä S.To test whether, in horses, the concentration of muscle glycogen can be influenced by increasing the uptake of glucose into the muscle cells or by providing a gluconeogenic precursor, 9 trained half-bred riding horses performed on a treadmill a 1.5 h competition exercise test (CET). Each horse performed CET 3 times and 30 min after CET, each was given one of the following solutions: isotonic glucose-electrolyte (GE) solution, GE supplemented with 50 g leucine (GEL) to increase insulin secretion, or GE supplemented with 200 ml propionic acid (GEP), a gluconeogenic precursor. Administration of G...
Lewis N, Hinrichs K, Leese HJ, McGregor Argo C, Brison DR, Sturmey RG.The use of in vitro embryo production in the horse is increasing in clinical and research settings; however, protocols are yet to be optimised. Notably, the two most commonly used base media for in vitro maturation (IVM) supply glucose at markedly different concentrations: physiological (5.6 mM, M199) or supraphysiological (17 mM, DMEM/F-12). Exposure to high glucose has detrimental effects on oocytes and early embryos in many mammalian species, but the impact has not yet been examined in the horse. To address this, we compared the energy metabolism of equine COCs matured in M199-based maturat...
D'Silva C.Equine liver glutathione S-transferase has been shown to consist of two identical subunits of apparent Mr 25,500 and a pl of 8.9. Kinetic data at pH 6.5 with 1-chloro-2,4-dinitrobenzene as a substrate suggests a random rapid-equilibrium mechanism, which is supported by inhibition studies using glutathione analogues. S-(p-Bromobenzyl)glutathione and the corresponding N alpha-, CGlu- and CGly-substituted derivatives have been found, at pH 6.5, to be linear competitive inhibitors, with respect to GSH, of glutathione transferase. N-Acetylation of S-(p-bromobenzyl)glutathione decreases binding by 1...
Harvey JW, Stockham SL, Scott MA, Johnson PJ, Donald JJ, Chandler CJ.This report describes erythrocyte biochemical findings in an adult Spanish mustang mare that exhibited persistent methemoglobinemia, eccentrocytosis, and pyknocytosis that were not related to the consumption or administration of an exogenous oxidant. The methemoglobinemia was attributed to a deficiency in cytochrome-b5 reductase (Cb5R) activity, and the eccentrocytes and pyknocytes were attributed to a marked deficiency in reduced nicotinamide adenine dinucleotide phosphate-dependent glutathione reductase (GR) activity that resulted in decreased reduced glutathione concentration within erythro...
Turkan F, Harbi Calimli M, Akgun A, Gulbagca F, Sen F.Benzimidazoles are antiparasitic drugs having an extensive application field like agriculture, medicine, and especially in veterinary medicine. In this study, we report the effect of some benzimidazole drugs such as ricobendazole (RBZ), thiabendazole (TBZ), albendazole (ALBA) and oxfendazole (OFZ) on glutathione s-transferase (GST) enzyme activity. The kinetics studies, IC and Ki values of the tested drugs on GSTs enzyme activity were investigated. The obtained ranking of IC values were found to be approximately RBZ (53.31 μM, r 0.9778) < OFZ (57.75 μM, r 0.9630) < ALBA (63.00 μM, r 0...
Dechant JE, Baxter GM, Frisbie DD, Trotter GW, McIlwraith CW.Clinical trials in human and veterinary literature have documented the benefits of oral nutraceutical joint supplements containing glucosamine (GU) and chondroitin sulphate (CS) to treat mild to moderate osteoarthritis, but the effects of these components have not yet been conclusively determined. Objective: To assess varying dosages of GU and CS on normal and interleukin-1alpha (IL-1) conditioned equine cartilage explants and rationalise the use of these products. Objective: Treatment would not be detrimental to cartilage metabolism and higher dosages and the combination of GU and CS would be...
Elroy NN, Rogers J, Mafi GG, VanOverbeke DL, Hartson SD, Ramanathan R.Our objectives were to determine the non-enzymatic metmyoglobin reduction properties of bovine, porcine, and equine myoglobins and to characterize the effects of pre-incubation of 4-hydroxy-2-nonenal (HNE) with myoglobins on non-enzymatic metmyoglobin reduction in vitro. Purified bovine, porcine, and equine metmyoglobins (0.05 mM) were reduced at pH 5.6 and 7.4 in the presence or absence of HNE. Rates of metmyoglobin reduction were monitored by spectrophotometry, and myoglobin adducts were characterized by high-resolution mass-spectrometry. Results showed that the species origins of individual...
MacDonald MH, Stover SM, Willits NH, Benton HP.Explant cultures were set up, using articular cartilage obtained from metatarsophalangeal joints of 11 horses. Explants from 2 horses were used to determine culture conditions appropriate for tissue viability. The cartilage explants maintained steady-state metabolism of proteoglycans during a 13-day evaluation period. The metabolic response of equine articular cartilage to incubation with recombinant human interleukin 1 (0.01 to 100 ng/ml) was studied, using cartilage obtained from the remaining 9 horses, age of which ranged from 3 months to 20 years. Interleukin 1 induced a dose-dependent rel...
Skiöldebrand E, Ley C, Björklund U, Lindahl A, Hansson E.Osteoarthritis is a pain-associated progressive disease and pain mediators, such as opioid receptors, expressed in articular cartilage could represent novel therapeutic targets. Acute and chronic stages of OA indicate different metabolic abilities of the chondrocytes depending on inflammatory state. This study aimed to investigate the response of healthy and osteoarthritic chondrocytes and their expression and release of pain mediators in response to acute inflammation. Interleukin-1 beta (IL-1β) and lipopolysaccharide (LPS) were used to induce an acute inflammatory response in cultured equin...
Kallio PT, Tsai PS, Bailey JE.Expression of a gene encoding hemoglobin (VHb) from the aerobic bacterium Vitreoscilla sp. in several organisms, including Escherichia coli, has been shown to improve microaerobic cell growth and enhance oxygen-dependent product formation. The suitability of VHb to enhance microaerobic metabolism has been suggested to depend on its unusual oxygen binding characteristics. To examine whether hemoproteins of other origins can also elicit the positive effects VHb exerts in microaerobic E. coli cells, we subcloned the genes encoding Vitreoscilla VHb, horse heart myoglobin (HMb), and yeast flavohemo...
Muesing RA, Miller VT, LaRosa JC, Stoy DB, Phillips EA.Administration of conjugated equine estrogen to 31 postmenopausal women for 3 months produced 14.6% and 9.4% decreases in low density lipoprotein cholesterol (LDL-C) and apolipoprotein-B (apoB), and 11.5%, 12.7%, and 9.6% increases in high density lipoprotein cholesterol (HDL-C), apoA-I and apoA-II, respectively. Phospholipids of HDL2 and HDL3 were increased 57.9% and 19.3%, respectively, while relatively small increases in cholesterol of the two subfractions were not significant. Compositions of LDL and HDL and its subfractions were altered substantially with estrogen treatment. The proportio...
Weitnauer E, Robitzki A, Layer PG.Several side activities have been attributed to butyrylcholinesterase (BChE), including aryl acylamidase (AAA) activity, which is an amidase-like activity with unknown physiological function splitting the artificial substrate o-nitroacetanilide. For avians, extensive developmental data have pointed to neurogenetic functions of BChE, however, a possible AAA activity of BChE has not been studied. In this study, we first compare the relative levels of AAA exhibited by BChE in whole sera from chick, fetal calves (FCS) and horse. Remarkably, FCS exhibits a 400-fold higher ratio of AAA/BChE than hor...
Singh RK, Kooreman KM, Babbs CF, Fessler JF, Salaris SC, Pham J.The scavenging of superoxide radicals by endogenous and therapeutically administered superoxide dismutases may prevent superoxide-mediated oxidative stress leading to lipid peroxidation, membrane lysis, and cell death in a wide variety of normal and pathologic states. Simple inorganic manganous salts such as MnCl2 also have superoxide dismutase-like activity and are extremely inexpensive, compared with enzymatic superoxide dismutase preparations. In this study, we explored the use of Mn salts as antioxidant drugs. We used the percentage of inhibition of nitroblue tetrazolium reduction by super...
The Journal of physiologySeptember 1, 1975
Volume 250, Issue 3 633-649 doi: 10.1113/jphysiol.1975.sp011074
Johnson KG.1. A technique for perfusion of skin has been used to investigate a possible neurochemical basis for the different patterns of sweating in domestic animals. Evaporative water loss was measured from excised trunk skin, ears or tails perfused with a nutrient Krebs solution, to which drugs were added as required. Perfused skin was observed to sweat in response to administration of sudorific drugs, and some features of the patterns of sweating were similar to those which could be induced by heating or by drugs in conscious animals. 2. In sheep and goat skin, injections of adrenaline, and to a less...
Myćka G, Ropka-Molik K, Cywińska A, Szmatoła T, Stefaniuk-Szmukier M.Recent studies have shown that in Arabian horse muscle, long-term exercise-induced expression of genes related to fatty acid degradation and the downregulation of genes belonging to the glycolysis/gluconeogenesis and insulin signalling pathways. Long-lasting physical exertion may trigger the metabolism to switch the main energy source from carbohydrates to lipids due to higher caloric content. Objective: To describe the metabolism adaptation at the whole transcriptome of blood to endurance effort in Arabian horses. Methods: In vivo experiment. Methods: Venous blood samples from 10 Arabian hors...
Lin J, Merryweather J, Vitello LB, Erman JE.The kinetics of formation and dissociation of the horse metmyoglobin/azide complex has been investigated between pH 3.5 and 11.5. The ionic strength dependence of the reaction has been determined at integral pH values between 5 and 10. Hydrazoic acid, HN3, binds to metmyoglobin with a rate constant of (3.8 +/- 1.0) x 10(5) M-1 s-1. Protonation of a group with an apparent pKa of 4.0 +/- 0.3 increases the rate of HN3 binding 6.5-fold to (2.5 +/- 0.8) x 10(6) M-1 s-1. The ionizable group is attributed to the distal histidine, His-64. The azide anion, N-3, binds to metmyoglobin with a rate constan...
Katz LM, Bayly WM, Hines MT, Sides RH.Horses exercising at > or = approximately 90% VO2max develop arterial hypoxaemia with concurrent hypercapnoea, whereas ponies exercising at comparative levels become hypocapnoeic and maintain arterial oxygen tensions close to resting values. We sought to investigate the possibility that these differences relate to the ventilatory responses of these animals to exercise. Six Thoroughbred horses weighing mean +/- s.e. 501 +/- 27 kg and 5 ponies weighing mean +/- s.e. 164 +/- 18 kg exercised for 2 min on a 10% slope at speeds calculated to require 60% VO2max and for at least 1 min at speeds cal...
Vervuert I, Coenen M, Bothe C.This study was conducted to evaluate the effects of different corn processing techniques on the glycaemic and insulinaemic responses in horses. It was hypothesized that the changes in pre-caecal starch digestibility caused by various types of corn processing would alter the post-prandial glycaemic and/or insulinaemic response. Six horses were fed in random order: untreated, finely ground, steamed, micronized, steam-flaked and popped corn. The total corn intake was adjusted to 630 g starch/horse/day (1.2-1.5 g starch/kg BW/day). During a stabilization period of 10 days, horses also received 6 k...
Elzinga SE, Rohleder B, Schanbacher B, McQuerry K, Barker VD, Adams AA.Extracts derived from the leaves of the stevia plant (stevioside) are commonly used as sweeteners for humans and horses. Stevioside appears to be safe for human consumption, including for individuals with insulin dysregulation. In the horse, the safety or metabolic effects of stevioside on normal animals or on those with metabolic dysfunction are unknown. Furthermore, the inflammatory response to a glycemic challenge or to stevioside in horses is not well defined. Therefore, the objective of this study was to measure the effects of stevioside and a glycemic challenge on insulin, glucose, and i...
Delatour P, Benoit E, Bourdin M, Gobron M, Moysan F.After the administration of racemic ketoprofen and carprofen to man, both enantiomers of each compound exhibit similar plasma profiles. This contrasts with the rat where the active S(+) enantiomer is predominant. For carprofen, regardless of the route of administration, the R(-) enantiomer is predominant in the plasma of all investigated animal species. The S(+)/R(-) ratio of the "areas under the curves" during the time course of the kinetics, is: 0.60 in dogs, 0.53 in Yucatan micro-pigs, 0.48 in mini-goats, 0.67 in calves and 0.19 in horses. For ketoprofen, the S(+) enantiomer is predominant ...
Microscopy research and techniqueJuly 1, 1997
Volume 38, Issue 1-2 115-124 doi: 10.1002/(SICI)1097-0029(19970701/15)38:1/2<115::AID-JEMT12>3.0.CO;2-S
Ridderstråle Y, Persson E, Dantzer V, Leiser R.The placenta has multiple functions, being the organ which provides oxygen and nutrients to the developing conceptus. In the placenta, the enzyme carbonic anhydrase (CA) may provide ions for exchange with Na+, K+, and Cl- in transepithelial movement of ions and fluid, as well as facilitating carbon dioxide diffusion. It can also be active in intermediary metabolism, such as gluconeogenesis, urea, and fatty acid synthesis. Placental material from pig, horse, cow, mink, rat, and human was therefore investigated, representing placenta types with variations in shape, internal architecture, and nat...
Subhahar MB, Singh J, Albert PH, Kadry AM.Celecoxib, a nonsteroidal anti-inflammatory drug, is frequently used to treat arthritis in humans with minimal gastrointestinal side effect compared to traditional NSAIDs. The primary aim of this study was to determine the pharmacokinetic profile of celecoxib-a selective cyclooxygenase-2 (COX-2) inhibitor in horses. Six horses were administered a single oral dose of celecoxib at 2 mg/kg (body weight). After oral dosing, the drug reached a maximum concentration (mean ± SD) in blood of 1,088 ± 324 ng/ml in 4.58 hr. The elimination half-life was 13.60 ± 3.18 hr, and the area under th...
Price JS, Jackson BF, Gray JA, Harris PA, Wright IM, Pfeiffer DU, Robins SP, Eastell R, Ricketts SW.This study describes longitudinal changes in serum levels of biochemical markers of bone cell activity in a group of 24 thoroughbred foals from birth to 18 months of age. The markers of bone formation included the type I collagen carboxy-terminal propeptide (PICP), the bone-specific isoenzyme of alkaline phosphatase (BAP), and osteocalcin (OC). Levels of the cross-linked telopeptide of type I collagen (ICTP), a marker of bone resorption, and the N-terminal propeptide of type III collagen (PNIIIP), a marker of soft tissue turnover, were also measured. Levels of all markers fell significantly be...
Muñoz A, Santisteban R, Rubio MD, Agüera EI, Escribano BM, Castejón FM.The effects of two training programmes in 20 Andalusian and 12 Anglo-Arabian horses were evaluated by an increasing intensity work test at velocities of 4, 5, 6, 7 and 8 m sec(-1). Heart rate was monitored and blood samples were drawn at rest and after each velocity to analyse packed cell volume, haemoglobin concentration, plasma lactate and potassium levels. Furthermore, the programmes were video-taped and stride length, duration and frequency, stance (restraint and propulsion), swing phase durations and stride vertical component were measured. The training protocol of the Andalusian horses p...
Art T, Franchimont P, Lekeux P.Ten horses underwent a standardised strenuous treadmill exercise test, before, during and after which measurements were made of plasma beta-endorphin and cortisol concentrations, blood lactate, glucose, haemoglobin and pH, the activities of creatine kinase, lactate dehydrogenase and aspartate amino-transferase, and heart rate, oxygen uptake and expired minute volume. The correlations between the exercise-induced response of beta-endorphin and the changes observed in the other physiological measurements were examined. There was a large variation in the beta-endorphin response of the horses to e...
De Leo M, Giorgi M, Saccomanni G, Manera C, Braca A.Tramadol is a centrally acting analgesic drug that has been used clinically for the last two decades to treat pain in humans. The clinical response of tramadol is strictly correlated to its metabolism, because of the different analgesic activity of its metabolites. O-Desmethyltramadol (M1), its major active metabolite, is 200 times more potent at the micro-receptor than the parent drug. In recent years tramadol has been widely introduced in veterinary medicine but its use has been questioned in some species. The aim of the present study was to develop a new sensible method to detect the whole ...
Pratt-Phillips S.Obesity is an important health concern in horses, along with humans and companion animals. Adipose tissue is an inflammatory organ that alters the insulin-signaling cascade, ultimately causing insulin dysregulation and impaired glucose metabolism. These disruptions can increase the risk of metabolic disease and laminitis in horses and may also impact energy metabolism during exercise. A single bout of exercise, along with chronic exercise conditioning, increases insulin sensitivity and glucose disposal via both contraction- and insulin-mediated glucose uptake pathways. Regular exercise also in...
