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Topic:Biochemistry
The study of biochemistry in horses encompasses the chemical processes and substances that occur within equine organisms. This field investigates the molecular interactions and pathways that are fundamental to horse physiology, including metabolism, enzyme activity, and genetic expression. Key areas of interest include the examination of metabolic disorders, nutrient absorption, and the biochemical basis of muscle function and energy production. Researchers utilize biochemical analysis to understand health and disease mechanisms in horses, contributing to the development of diagnostic tools and therapeutic strategies. This page gathers peer-reviewed studies and scholarly articles that explore various biochemical processes and their implications for equine health and performance.
Predicted secondary structure of horse muscle acylphosphatase. Comparison with circular dichroism measurements. We have predicted the secondary structure of horse muscle acylphosphatase by the statistical method of Chou and Fasman. In addition, we have studied the circular dichroism spectra of the enzyme, obtaining values for comparison to the predicted results. Discrepancies were found for the alpha-helix content estimated by the two methods.
Influence of dietary molybdenum on copper metabolism in ponies. The effects of molybdenum ingestion on copper metabolism were investigated in bile duct-cannulated ponies fed diets containing 1.01, 27.4 and 107.3 ppm molybdenum. Copper metabolism was assessed by examination of 64Cu and stable copper excretion in feces, bile and urine. The addition of molybdenum to the diet decreased copper absorption and retention as a consequence of increased excretion of dietary copper in feces and increased excretion of absorbed copper in bile. Only 5% or less of the absorbed copper was excreted in urine regardless of dietary treatment. Biliary molybdenum excretion was o...
In vivo metabolism of [3H]equilin in the pregnant mare. [3H]Equilin [3H-labeled 3-hydroxy-1,3,5(10), 7-estratetraen-17-one] was administered iv to a pregnant mare in the 10th month of gestation. Maternal urine was collected for 3 days, and blood samples were taken 35 min and 3, 6, 12, and 24 h after the injection. The half-life of the disappearance of radioactivity from the blood was approximately 2.5 h. Over 90% of the administered dose was excreted in the first 24 h. The urine was extracted, hydrolyzed, and fractionated. The bulk of the radioactive material (75%) was present in the phenolic sulfate fraction from which radiochemically pure equilin...
Characterization of the binding of Triton X-100 to equine and rabbit serum albumin. The binding isotherms for Triton X-100 binding to equine and rabbit serum albumin were determined by equilibrium dialysis at 16 degrees C in pH 7.0, I = 0.05 phosphate buffer. Presented in a Scatchard plot, the binding isotherms are a straight line, indicating thermodynamically independent and identical binding sites. In this model equine serum albumin is characterized as having 11 such sites with an equilibrium constant of 6.0 x 10(3) M-1. Similarly, rabbit serum albumin is characterized as having 9 such sites with an equilibrium constant of 8.0 x 10(3) M-1.
The metabolism of promazine and acetylpromazine in the horse. Promazine hydrochloride and acetylpromazine maleate were administered intravenously at clinical dose levels to horses. In urine from horses given promazine hydrochloride, the parent drug and four metabolites were detected. The two major metabolites, present as conjugates were identified after hydrolysis by beta-glucuronidase/arylsulfatase as 3-hydroxypromazine and 3-hydroxydesmonomethyl-promazine. Conjugated 3-hydroxypromazine has been previously identified as a major metabolite in the horse. Two minor metabolites isolated in this study were primaizine N-oxide and promazine N-oxide sulfoxide. ...
Copper metabolism and requirement in mature ponies. The effects of copper intake on stable copper and 64Cu metabolism and on the excretory pathways of absorbed copper were examined in ponies. Bile and feces collected from two bile duct-cannulated ponies following an intravenous dose of 64Cu showed that bile was the main route of endogenous copper excretion. Stable copper and 64Cu metabolism were examined in three intact ponies fed dietary copper to provide 5.6, 16.6 and 25.7 mg Cu/100 kg body weight/day. The amount of copper excreted in urine was not influenced by dietary treatment. Stable copper absorption and 64Cu retention significantly incr...
[Some clinical biochemical features of ‘tying up’ in horses (author’s transl)]. The changes in the activities of lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) in de blood of thirty-three horses with 'tying up' were compared. The extent to which the serum enzymes LDH, CPK and glutamic oxaloacetic transaminase (GOT) and the changes in the activities of these enzymes after suitable labour can be used in the diagnosis of 'tying up' and in following the recovery of patients was studied.
A biochemical study of the Arab Horse Society’s marathon race. Blood samples were taken before and after a cross country race over the marathon distance of 42 km. There was a rise in blood glucose and plasma free fatty acids and glycerol associated with a rise in plasma cortisol and glucagon but the fall in insulin was not significant (P > 0.05). Plasma potassium and albumin concentrations increased, calcium decreased and there was no change in sodium or bicarbonate concentrations. There was an increase in plasma urea, creatinine, uric acid, bilirubin and isocitrate dehydrogenase but no change in alkaline phosphatase. There was a rise in plasma creatin...
Fractionation and partial characterization of alpha-1-protease isoinhibitors of horse. The principal alpha-1-protease inhibitor of horse was fractionated by classical methods and analysed with a modified fibrinogen-agarose gel electrophoretic method of high sensitivity and resolving power. Starting with an electrophoretically homogeneous inhibitor in unfractionated serum, two isoinhibitor bands became apparent after fractionation with (NH4)2SO4 and DEAE-cellulose DE-52 ion-exchange chromatography. The isoinhibitors differed in electrophoretic migration and in the elution pattern from Sephadex G-100 gel filtration, but possessed identical antigenic determinants and enzyme specifi...
Effects of copper pretreatment upon toxicity of selenium in ponies. Thirty-four adult ponies were used to determine the effects of single oral doses of copper (Cu) supplements (0, 20, and 40 mg of Cu/kg of body weight) on the toxicity of oral doses of selenium (Se) supplements (0, 2, 4, 6, and 8 mg of Se/kg of body weight) administered 24 hours after the copper was given. Signs of Se toxicosis-sweating, diarrhea, tachycardia, tachypnea, mild pyrexia, lethargy, and colic-developed in ponies given 6 and 8 mg of Se/kg of body weight without Cu pretreatment. Two of 4 ponies given 6 mg of Se/kg and both ponies given 8 mg of Se/kg without Cu pretreatment died within...
Characterization of equine alkaline phosphatase isoenzymes based on their electrophoretic mobility by polyacrylamide gel disc electrophoresis. Alkaline phosphatase isoenzymes of equine tissues, peritoneal fluid, and serum were characterized by their electrophoretic mobilities, using polyacrylamide gel disc electrophoresis. The alkaline phosphatase isoenzymes in liver, kidney, spleen, small intestine, placenta, bone, small colon, and large colon tissue samples were extracted and separated by electrophoresis. The resulting isoenzyme mobilities and spectrophotometric scans were evaluated for their tissue specificity and for their possible use in determining the tissue contribution of alkaline phosphatase to serum and peritoneal fluid. T...
Dietary fat and exercise conditioning effect on metabolic parameters in the horse. Four isocaloric diets containing 4, 8, 12 and 16% dietary fat (as soybean oil) were fed to four horses at four intervals according to a Latin square design. After 3 weeks of conditioning at each interval, diet effects were evaluated by trotting all horses at 3.2 m/sec for 6 hours. Pre- and posttrotting responses were measured in muscle and liver glycogen, serum long-chain fatty acids, serum electrolytes, serum enzymes, serum cholesterol, plasma glucose, packed cell volume and hemoglobin. Dietary fat was highly correlated with exercise-induced plasma glucose changes and with cholesterol concent...
Equine postanesthetic forelimb lameness: intracompartmental muscle pressure changes and biochemical patterns. Intracompartmental muscle pressures were recorded from the right and left forelimbs (extensor carpi radialis, triceps brachii) of healthy horses maintained in left lateral recumbency while under deep halothane anesthesia for 180 to 240 minutes. Cardiac output, blood pressure, blood gases, and acid-base status were monitored throughout the anesthesia, and electrolyte levels (Ca2+, P+, K+, Cl-, Na+) and enzyme activities (aspartate aminotransferase (AST), creatine phosphokinase (CPK), and blood lactate) were monitored for 7 days. Postanesthetic forelimb lameness was produced in 5 of the 6 horses...
[Effect of 2 methods of demineralization on the on the preservation of glycoproteins and proteoglycans in the intertubular and peritubular dentin in the horse]. The effect of 2 methods of demineralization on the preservation of proteoglycans and glycoproteins was studied in the intertubular and peritubular dentine of the horse. The specimens embedded in Epon were demineralized with a 2% acid formic solution (Bonucci and Gheradi, 1975). Other fragments were treated with an organic solution of EDTA alkylammonium salt (Scott and Kyffin, 1979). These methods preserved in a satisfactory way these labile organic components. In the intertubular dentine, glycoproteins and proteoglycans were also identified, either associated with collagen fibres as a glue and...
Helix packing and subunit conformation in horse spleen apoferritin. An electron density map of horse spleen apoferritin at 0.28-nm (2.8 A) resolution and its preliminary interpretation have been described previously. Rigorous examination of this and newer maps at the same nominal resolution but calculated from more extensive data sets, including model building in a Richards' comparator, now allows us to report on structural features in more detail. We list inter-helical angles within and between neighbouring subunits, and describe a new short region of inter-subunit anti-parallel pleated sheet. A short section of electron density not properly accounted for in ...
[The immunological relation between human and equine Gc proteins (author’s transl)]. The immunological comparison of human and equine Gc proteins showed partial identical reactions between both species. Immunizations of goats and rabbits with horse serum produced antisera able to recognize human Gc proteins.
Comparison of milk and blood plasma progesterone concentrations in cycling and pregnant mares. Progesterone concentrations were measured in milk and blood plasma for 15 mares throughout a normal estrous cycle and early pregnancy to determine the feasibility of utilizing progesterone in milk as an indicator of pregnancy. Samples were obtained daily from foaling until diagnosis of pregnancy by rectal examination at 30 to 35 days of gestation. Progesterone in milk and blood plasma was quantified by radioimmunoassay. Mean progesterone concentrations (+/- SE) in plasma from foaling to foal heat and during estrus, luteal phase and pregnancy were .51 +/- .09 ng/ml, .53 +/- .08 ng/ml, 3.88 +/- ...
The major metabolite of fentanyl in the horse. Fentanyl, a potent, synthetic narcotic analgesic, has reportedly been used to "dope" racehorses. Urine was collected from a horse dosed with 70 mg of [3H]fentanyl, and the primary metabolite, a water-soluble, amphoteric compound, was isolated by high-pressure liquid chromatography and identified by spectroscopic analysis. This metabolite was found to be N-[1-(2-phenethyl-4-piperidinyl)] malonanilinic acid.
Conformation of Immunoglobulin M. III. Structural requirements of antigen for complement fixation by equine IgM. Complexes of IgM equine anti-dansyl antibodies and different dansyl substituted carriers were tested for their ability to fix complement (C). Only dansyl92-Ficoll and dansyl12-poly-L-lysine were found to be effective. Dansyl13-bovine serum albumin, dansyl127-keyhole limpet hemocyanin, and reduced and alkylated dansyl10-ribonuclease were all ineffective. Lack of C fixation by the dansyl-ribonuclease was not due to lack of antibody-antigen complex formation, since binding at the concentrations employed for C fixation was established. However, in contrast, polymerized dansyl-ribonuclease (polydis...
Effect of pyrrolizidine alkaloid-induced hepatic disease on plasma amino acid patterns in the horse. Plasma amino acid patterns were studied in 6 clinically normal adult horses during the course of hepatic disease induced by feeding them plants containing pyrrolizidine alkaloids. At death, there were significant (P less than 0.01) increases in glutamine, proline, tyrosine, asparagine, lysine, histidine, alanine, phenylalanine, methionine, aspartic acid, and ornithine values. There were no significant changes in glycine, valine, isoleucine tryptophan, and arginine values. There were significant (P less than 0.01) decreases in citrulline. Ammonia increased 4-fold. Alpha-Aminoadipic acid and alp...
Selected ion monitoring assay for bromhexine in biological fluids. A method has been developed for quantification of bromhexine in plasma using gas chromatography mass spectrometry with selected ion monitoring. A deuterium labelled analogue was synthesized and used as the internal standard. To evaluate the gas chromatographic electron capture detection method described earlier, 23 plasma samples have been analysed by both techniques. Although a good correlation was shown, selected ion monitoring was superior to the electron capture detection method for levels below 3 ng ml-1. The mass spectrometric method has also been used to set up a pharmacokinetic study o...
Sequence of the low activity equine erythrocyte carbonic anhydrase and delineation of the amino acid substitutions in various polymorphic forms. the sequence of the low activity form of equine erythrocyte carbonic anhydrase has been determined. The most common electrophoretic form, designated D, has been found to have five substitutions. Amino acid exchanges in the electrophoretic variants known as A1, A2, B, and T have been found at six other positions. The data do not permit calculation of the number of polymorphic forms of this enzyme. The equine D isozyme and the analogous human enzyme are quite homologous, 211 of their 260 residues, or 81%, being identical.
[3H]5-HT binding sites and 5-HT-sensitive adenylate cyclase in glial cell membrane fraction. Glial cell membrane fractions were prepared using glial cells preparations isolated from horse brain striatum. [3H]5-HT binding was measured by the filtration technique and the adenylate cyclase activity determined by measuring the cAMP production using a radioimmunoassay. Serotonin binds to glial membrane fractions with an affinity corresponding to a dissociation constant Kd = nM. The corresponding site is serotoninergic specific: [3H]5-HT binding is inhibited by 5-HT agonists (5 OH NM-DMT, 5-MeOHT, 5-MeOH-DMT, NN-DMT) or antagonists (cinanserine, cyproheptadine, methysergide, LSD) and not (o...
Histochemical properties of muscle fibres types and enzyme activities in skeletal muscles of Standardbred trotters of different ages. Fibre characteristics and enzyme activities were determined for the gluteus, semitendinosus, vastus lateralis and triceps brachii muscles of 55 Standardbred trotters of different ages. Four fibre types (I, IIA, IIB, IIC) were demonstrated by histochemical staining of myofibrillar adenosine triphosphatase after preincubation at different pH values. Type II fibres predominated in all the muscles and the type IIA/IIB ratio was higher in horses over 5 years than in younger horses, except in the vastus in which the IIA/IIB ratio did not change with age. The vastus had the highest proportion of type...
Characterization of gangliosides from equine kidney and spleen. Gangliosides were isolated from equine kidney and spleen, and their carbohydrate and lipid moieties were characterized. Among the long-chain bases, considerable proportions of trihydroxy bases (42.3 to 61.2% of the total bases), in which phytosphingosine was predominant were found in all the ganglioside classes. The other major base was sphingosine. Among the constituent fatty acids, long-chain acids (with a carbon number of more than 20), comprised approximately half the total acids, with some alpha-hydroxy and mono-unsaturated acids. By means of sequential hydrolysis with glycosidases couple...
