Glycolysis is a metabolic pathway that involves the enzymatic breakdown of glucose to produce energy in the form of adenosine triphosphate (ATP) in horses. This process occurs in the cytoplasm of cells and is a critical component of cellular metabolism, providing energy for various physiological activities. Glycolysis consists of a series of ten enzyme-catalyzed reactions that convert glucose into pyruvate, with the concomitant production of ATP and nicotinamide adenine dinucleotide (NADH). In horses, glycolysis is particularly important during periods of intense exercise or when rapid energy production is required. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and physiological implications of glycolysis in equine muscle tissue and overall metabolic health.
Lewis J, Poland J.The ability of erythromycin in liquid medium to suppress the growth of eight species of acholeplasma and of 13 species of mycoplasma was tested. The Acholeplasma spp and two glycolytic Mycoplasma spp from horses--a slow glucose-metabolising (SGM) mycoplasma and a strain N3, related to M mycoides--were sensitive to erythromycin. Thus the growth of acholeplasmas can be suppressed when attempts are made to isolate pathogens from the porcine respiratory tract, but, in the case of horses, erythromycin would suppress not only Acholeplasma spp but also two Mycoplasma spp of unknown pathogenicity in t...
Franken P, Schotman JH.The activities and concentrations of a number of erythrocytic enzymes and intermediate products of erythrocyte metabolism were determined in twenty-one normal standard-bred horses which were studied clinically and biochemically. These studies showed that equine anaerobic glycolysis is characterized by a biochemical pattern similar to that observed in human PK deficiency. The greater sensitivity of equine haemoglobin to oxidants is attributable either to low stability of GSH, which may be due either to the low activity of GR or that of 6PGD as observed in the studies. In addition, the saturatio...
Snow DH, Mackenzie G.The effects of intermittent maximal exercise (galloping) before and after a 10 week training programme were studied in 6 horses. Determinations were carried out on venous blood for packed cell volume, total plasma protein, glucose, glycerol, free fatty acids, lactate, 11-hydroxycorticosteroids, blood gases and pH. There were marked changes associated with galloping and some of these could be modified with training. The major findings included (i) an elevated blood glucose, (ii) a large increase in glycerol, which was greatest at 30 min post-exercise and was higher following training, (iii) sma...
Anderson MG, Aitken MM.Adrenaline was given intramuscularly to resting horses. It increased heart rate, sweating, blood levels of lactic dehydrogenase, aldolase, creatine kinase, glucose, lactate, free fatty acids and glycerol. Responses to isoprenaline, to noradenaline and to adrenaline after pretreatment with propranolol indicated that beta receptors were involved in stimulation of tachycardia, sweating, lipolysis and muscle glycogenolysis, and alpha receptors in stimulation of liver glycogenolysis and leakage of intracellular enzymes. The time course and relative magnitude of the effects on different enzymes was ...
Johnson PE, Maister SG, Knowles JR.Phosphoglycerate kinase has been isolated in crystalline form from horse muscle. A convenient isolation procedure is described that yields homogeneous enzyme of specific activity 700 units/mg (30 degrees C). The enzyme is monomeric, and has a molecular weight 47 000. Of the eight cysteine residues in the protein, two react rapidly with Nbs21 with the concomitant loss of the catalytic activity. Since the isolation of phosphoglycerate kinase from yeast (Bücher, 1955) there have been several reports of purification methods yielding enzyme approaching molecular homogeneity, from rabbit muscle (Be...
Smith JE, Agar NS.Anaemic horses do not provide reticulocytes during an erythropietic response. Acute blood loss was studied in 4 ponies as a model to monitor changes in erythrocyte metabolism during active erythropoiesis. Following phlebotomy, erythrocyte adenosine-5-triphosphate, adenosine-5-diphosphate, glucose-6-phosphate, fructose-6-phosphate, and phosphoenolpyruvate increased signifcantly. The remaining glycolytic intermediates did not change. It is suggested that the determination of erythrocyte adenosine-5-triphosphate may be used to evaluate erythrocyte response following acute blood loss in the horse....
Mann T.Stallion semen has several chemical characteristics not commonly encountered in other animals. It contains very little fructose and the spermatozoa possess only limited fructolytic ability under anaerobic conditions. By determining some of the characteristic constituents such as ergothioneine, citric acid, glycerylphosphorylcholine and certain glycosidases, it is possible to obtain a quantitative measure of the secretory contribution of the ampulla, seminal vesicle and epididymis, respectively, towards the final composition of the whole ejaculate. By analysing separately the various fractions ...
Rawlings CA, Bisgard GE, Dufek JH, Buss DD, Will JA, Birnbaum ML, Chopra PS, Kahn DR.Prolonged extracorporeal membrane oxygenation (PEMO) was performed in 6 adult ponies with the membrane oxygenator in vein-to-artery bypass circuit. A flow rate equal to 46 per cent of control cardiac output was diverted through the PEMO circuit of 10 to 24 hours. Three of the 6 ponies were perfused for at least 20 hours and developed no complications. Immediately following initiation of PEMO, left ventricular output decreased; however, in the interval between 6 and 24 hours, left ventricular output was increased above control levels. Aortic pressure and left ventricular work were markedly elev...
Blake CC, Evans PR, Scopes RK.The single peptide chain of 3-phosphoglycerate kinase is folded into two distinct globular units, only one of which seems to be involved in substrate binding.
Ford EJ, Evans J.1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U-14C]glucose and [2-3H]glucose. 2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant. 3. After fasting the total entry rate fell from 1.44 +/- 0.11 (n4) to 1.19 +/- 0.12 mg/min per kg body-weight (P less than 0.01) and irreversible loss fell from 1.36 +/- 0.10 (n4) to 1.05 +/- 0.10 mg/min per kg body-weight (P...
Schott HC, Patterson KS, Eberhart SW.To determine whether administration of glycerol-containing solutions induces a state of transient hyperhydration in resting euhydrated horses, changes in plasma and urine constituents were measured in four horses for 1 h before and 5 h after nasogastric administration of each of four treatments (Experiment 1). Treatments were applied in a randomized fashion and included: (1) 1.0 g.kg(-)(1)glycerol in 8 L of water (G); (2) 8 L of water (W); (3) 8 L of 0.9% NaCl solution (S); and (4) 1.0 g.kg(-)(1)glycerol in 8 L of 0.9% NaCl solution (GS). In a subsequent study, voluntary water intake was measu...
Klinkhamer K, Menheere PP, van der Kolk JH.Glucocorticoids are suggested to precipitate laminitis and induce insulin resistance in horses. Objective: To assess insulin sensitivity and the basal amount of glucose metabolized in equine pituitary pars intermedia dysfunction (PPID). Methods: The euglycaemic hyperinsulinaemic clamp (EHC) technique was performed in seven horses with a diagnosis of PPID based on the presence of hypertrichosis and positive dexamethasone suppression-test results comprising one gelding and six mares with a mean age of 21.1 ± 5.8 (SD; range 15-34) years. Results were compared with those from five negative (h...
Brück I, Hyland JH.The contributions of 2 biochemical pathways to the total metabolism of glucose (the Embden-Meyerhof pathway [EMP] and the pentose phosphate pathway [PPP]), were assessed for equine embryos recovered on Day 4.5, 7.5 and 11.5 post ovulation. At all developmental stages studied, glucose was metabolized through both pathways. Through the EMP, the amounts of glucose metabolized per nl embryo volume per hour were 4.0, 9.9 and 3.1 pmol, whereas via the PPP, amounts were 0.9, 1.7 and 0.07 pmol for Day-4.5, -7.5 and -11.5 embryos, respectively. The ratio of EMP:PPP with age was 9.7 for Day -4.5 embryos...
Ronéus N, Essén-Gustavsson B.To determine whether performance capacity in a group of young trained Standardbreds is related to skeletal muscle characteristics and metabolic response to exercise. Methods: 13 clinically normal 2-year-old Standardbreds. Methods: Venous blood and middle gluteal muscle biopsy samples were obtained from each horse within 1 to 2 minutes after trotting at high speed for 1,600 m. Results: There was a positive correlation between plasma lactate and muscle glucose-6-phosphate (G-6-P) concentrations and trotting speed. There was a negative correlation between muscle adenosine triphosphate concentrati...
van den Hoven R, Meijer AE, Wensing T, Breukink HJ.Gluteal muscle specimens were taken from 4 horses. From 1 of the 4 gluteal muscles, serial sections were prepared. Individual muscle fibers were identified and studied, using photomicrographs of sections stained by different enzyme histochemical methods. In specimens in which cytoplasmic soluble enzymes were studied, use was made of the semi-permeable membrane technique to hamper enzyme diffusion into reaction fluids. Enzymes involved in glycogenolysis, glycolysis, the tricarboxylic acid cycle, synthesis of reduced nicotinamide adenine dinucleotide phosphate, the pentose phosphate cycle, the a...
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and values of pH were studied in standard-bred mares and their foals, for 13 weeks of foal life, throughout 2 years. 2. The studies began when a foal was 7 days old and were repeated every 2 weeks until foals reached 13 weeks of age. 3. Blood samples were taken every 4 hr for one day, each second week. 4. In the LA, PA levels and pH values no diurnal rhythm was stated in lactating mares during study periods. 5. In foals the diurnal rhythm in LA and PA occurred in the 3rd month of their life, with the acrophase at night ...
Meijer AE, van den Hoven R, Wensing T, Breukink HJ.Needle biopsies from m. gluteus medius of 22 horses which had suffered from repeated attacks of exertional myopathy were studied at various times after an attack, to determine if metabolic alterations can be demonstrated by enzyme histochemistry. Morphological changes and activity of 25 enzymes were studied. Immediately after onset of an attack, some large rounded fibres with a defect of the oxidative phosphorylation were seen. After some hours these fibres lost their glycolytic enzyme activity, followed by disappearance of mitochondrial enzyme activity with accumulation of Ca2+-containing sub...
Rice DW, Blake CC.Crystals of horse muscle 3-phosphoglycerate kinase have been grown in the presence of a wide variety of substrates using either potassium tartrate or polyethylene glycol as a precipitant. In those grown from polyethylene glycol, two related crystal forms have been obtained by varying the nature of the substrates present in the crystallization medium. In order to obtain one of these forms, form B, the presence of the substrate 3-phosphoglycerate appears to be essential. The two crystal forms are not interconvertible by simple diffusion experiments and the crystals grown in the absence of 3-phos...
Franken P, Schotman JH.The activities and concentrations of a number of erythrocytic enzymes and intermediate products of erythrocyte metabolism were determined in twenty-one normal standard-bred horses which were studied clinically and biochemically. These studies showed that equine anaerobic glycolysis is characterized by a biochemical pattern similar to that observed in human PK deficiency. The greater sensitivity of equine haemoglobin to oxidants is attributable either to low stability of GSH, which may be due either to the low activity of GR or that of 6PGD as observed in the studies. In addition, the saturatio...
Parillo F, Rossi G, Busoni V, Magi GE, Verini Supplizi A.The aim of this study was to investigate the carbohydrate composition of mucosubstances in the equine guttural pouches using conventional histochemical tests in conjunction with glycolytic digestion to degrade different classes of glycosoaminoglycans. In the goblet cells, the mucopolysaccharides contained chondroitin sulfate B, heparin, heparan sulfate and sialic acid residues. The acinar cells also expressed these substances (except for heparin), whereas the ductal cells produced chondroitin sulfate B and sialic acid. Neutral sugars were also found in each cell type. The diversity of the glyc...
Takahashi K, Mukai K, Ebisuda Y, Sugiyama F, Yoshida T, Hatta H, Kitaoka Y.Evidence suggests that positive pacing strategy improves exercise performance and fatigue tolerance in athletic events lasting 1-5 min. This study investigated muscle metabolic responses to positive and negative pacing strategies in Thoroughbred horses. Eight Thoroughbred horses performed 2 min treadmill running using positive (1 min at 110% maximal O uptake [V̇Omax], followed by 1 min at 90% V̇Omax) and negative (1 min at 90% V̇Omax, followed by 1 min at 110% V̇Omax) pacing strategies. The arterial-mixed venous O difference did not significantly differ between the two strategies. Pl...
Gong W, Ding W, Bou T, Shi L, Lin Y, Shi X, Wu H, Li Z, Dugarjaviin M, Bai D.Ferulic acid (FA), a natural antioxidant and major active component in Angelica sinensis, has beneficial effects on skeletal muscle health; however, its role in modulating muscle fiber type composition Mongolian horse remains unclear. In this study, we found that FA promotes the proliferation of Mongolian horse skeletal muscle satellite cell (MuSCs), upregulates the expression of fast-twitch muscle marker genes (e.g., MYH2), and downregulates the expression of slow-twitch markers (e.g., MYH7). RNA-seq revealed that FA activates the HIF-1 signaling pathway, significantly increasing PDK1 express...
Li X, Qian S, Yang L, Yang X, Chang X, Zeng Y, Meng J.This study aimed to investigate the relationship between genes and metabolites involved in glycogen metabolism across different tissues of Yili mares using joint transcriptomic and metabolomic analyses. Glycogen content was measured in various tissues (pincer, trapezius, latissimus dorsi, gluteus medius, semitendinosus, external abdominal obliques, liver, and heart) from seven Yili mares. The liver, as the visceral tissue with the highest glycogen content, and the gluteus medius, as the muscle with the highest glycogen content, were selected for transcriptomic sequencing and metabolomic analys...
Wang J, Li Z, Li L, Wang R, Ma S, Su Y, Shan D, Huang Q.Kazakh horses are renowned for their endurance and adaptability, with distinct muscle groups such as the longissimus dorsi (LD) and biceps femoris (BF) muscles serving specialized functions. However, the molecular mechanisms underlying the functional specialization of these muscles in Kazakh horses remain poorly understood. This study aims to address this gap by utilizing single-cell RNA sequencing (scRNA-seq) to investigate the transcriptomic differences between these muscle groups, with a focus on understanding their molecular adaptations. Our analysis revealed that the BF muscle, specialize...
Li X, Meng C, Xue Y, Shen Z, Ren W, Zeng Y, Meng J.Skeletal muscle is the largest organ system in mammals. To investigate the differences in energy metabolism across various skeletal muscles in Yili horses, this study examined muscle fiber type distributions through immunohistochemical staining of muscles, including the splenius, triceps brachii, longissimus dorsi, and gluteus medius. The splenius and gluteus medius muscles, which exhibited the greatest differences in the proportion of slow-twitch fiber area, were selected for further comparison of differential metabolites and transcriptomic expression profiles between slow-twitch and fast-twi...
Becerro-Rey L, Martín-Cano FE, Silva-Rodríguez A, Ortega-Ferrusola C, da Silva-Álvarez E, Ortiz-Placín C, Tapia JA, Gil MC, Peña FJ.Three isoforms of lactate dehydrogenase (LDH) - LDHA (cytoplasmic), LDHB (mitochondrial), and LDHC (flagellar) - have been identified and localized in stallion spermatozoa. Functional inhibition assays indicate that these three isoforms constitute a lactate shuttle of crucial importance for sperm function. Unassigned: Stallion spermatozoa use different energy sources; while oxidative phosphorylation predominates, glycolysis and beta-oxidation of fatty acids are also present. Glycolysis depends on the availability of NAD+ as an electron acceptor. During glycolysis, NAD+ is reduced to NADH. To e...
