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.
A preovulatory rise of dehydroepiandrosterone in the mare measured by radioimmunoassay. A radioimmunoassay procedure was developed for the measurement of dehydroepiandrosterone (DHA) in peripheral serum in nonpregnant mares. The synthesis and conjugation of 3beta-hydroxy-5-androsten-19-al-17-one 19(0-carboxymethyl) oxime is described. Antisera were developed against this antigen and characterized. The most specific antiserum was used to measure DHA. Concentrations of DHA were greatest immediately before ovulation.
Pharmacology of procaine in the horse: a preliminary report. Rapid intravenous injection of 1 g of procaine hydrochloride in Thoroughbred mares produced variable signs of central nervous system excitation for as long as 4 minutes. Plasma concentrations of procaine were similarly variable and transient, decreasing with a half-life of approximately 25 minutes. In vitro, plasma from freshly collected equine blood hydrolyzed procaine with a half-life of approximately 7.5 minutes. This hydrolysis was apparently due to plasma esterases. Penicillin, when added free or complexed as procaine-penicillin, did not protect procaine against hydrolysis by these plasma...
Utilization of proteins by the equine species. Protein digestion, nitrogen retention, plasma protein, plasma urea, and plasma-free amino acids were determined for ponies fed 3 different protein supplements. Substitution of casein, corn gluten meal, or corn gluten meal plus lysine for a portion of the cornstarch in a low-protein basal ration increased apparent digestion of protein. Substitution with either casein or corn gluten meal plus lysine produced a significant increase (P less than 0.05) in nitrogen retention, whereas the corn gluten meal substitution did not. Nitrogen retention, expressed as percentage of nitrogen absorbed, was incr...
Effects of environmental and other stressors on blood hormone patterns in lactating animals. Recent data on various environmental stressors and blood hormone patterns are presented for lactating cattle. Known stressor effects of such factors as environmental temperature, air pollution, and noise on the plasma thyroxine, growth hormone, cortisol, prolactin, progesterone, luteinzing hormone, epinephrine, and norepinephrine of lactating cattle are discussed. Information on stressor effects is lacking on glucagon, insulin, vasopressin, calcitonin, oxytocin, thyrotrophic hormone, follicle stimulating hormone, melatonin, parathyroid hormone, and estrogens in the lactating cow. The importanc...
Kinetics of the hydrolysis of synthetic substrates by horse urinary kallikrein and trypsin. The kinetic constants for horse urinary kallikrein and trypsin hydrolysis of BAEE, TAME, bradykinin methyl ester and bradykinyl-Ser-Val-Gin-Val-Ser were determined. The values of the ratio kcat/Km show that (1) kallikrein is catalytically less efficient than trypsin for all the substrates (2) the three esters are equally good substrates for trypsin while horse urinary kallikrein is 100-fold more effective on bradykinin methyl ester than on the other substrates (3) for both enzymes the ester of bradykinin is a better substrate than the tetradecapeptide.
Active-site labelling of kallikreins by chloromethylketone derivatives. Ala-Phe-Lys-CH2-Cl is a chloromethylketone derivative which is able to promote the inhibition of several proteolytic enzymes. In this paper the inhibition of horse urinary and plasmatic kallikreins is described and this inhibition is compared to that produced in human plasma kallikrein. This compound was designed based upon the structure of bradykinin. This enzyme substrate system can provide a model for the study of the interactions between bradykinin and its receptor. The inhibition of the enzymes was achieved both for its esterase and kinin-releasing activities.
The preparation and testing of antihuman lymphoblast globulin for clinical use. Antibodies to cultured human lymphoblasts were raised in horses using a schedule employing both subcutaneous and intravenous routes of injection. Plasma from groups of horses was pooled and the IgG prepared from each pool was tested extensively for safety and immunosuppressive efficacy in vitro and in vivo. On the basis of the results of skin grafting in monkeys, only globulins derived from the first main bleeds were blended to produce a bulk for clinical use. One early pool of globulin was discarded because when undiluted, it was lethal in monkeys by the intravenous route, and another pool wa...
Conformation of immunoglobulin M. I. Characterization of anti-epsilon-1-dimethylamino-5-naphthalenesulfonyl-L-lysine immunoglobulin M antibodies from horse, pig, and shark. IgM antibodies specific for the fluorophore epsiolon-1-dimethylamino-5-naphthalenesulfonyl-L-lysine(DNS-lysine) were elicited in the horse and nurse shark by immunization with a DNS-lysine streptococcal conjugate; the antibodies were purified by specific adsorption with an immunoadsorbent followed by gel filtration to select the IgM class (molecular weight 900 000). About 90% of the equine anti-DNS was IgM.DNS-Lysine, when bound in the combining sites of a population of these anti-DNS IgM antigodies from horse and nurse shark, as well as from pig, exhibited a marked fluorescence enhancement an...
Influence of azaperone/metomidate anaesthesia on blood biochemistry in the horse. Ponies were anaesthetized by administration of the ataractic, azaperone (0 · 2–0 · 8 mg/kg), in combination with the hypnotic, metomidate (3 · 5 mg/kg). Changes in blood biochemistry were measured during and following the course of action of these drugs. In control experiments, azaperone (0 · 4 and 0 · 8 mg/kg) was administered alone to other ponies. There were no significant changes in blood glucose concentration in either circumstance. Blood lactate and pyruvate concentrations and lactate/pyruvate ratio were not altered significantly by azaperone. However, moderate increases in lactat...
[Preparative isolation of alpha 2-macroglobulin, transferrin, albumin and study of their nonspecific gamma-inhibitory activity]. Profiles of distribution of non-specific gamma-inhibitors of influenza A2/Victoria/35/72 in donkey and horse sera were established by gel chromatography in Sephadex G-200. High and low molecular inhibitors were found in 19S and 4S serum fractions. Highly purified preparations of a2-macroglobulin, transferrine and albumin were isolated by a combination of methods of salt precipitation, gel chromatography on Sephadex G-100, G-200 and ion exchange on DEAE-Sephadex A-50. Heating sera resulted in a considerable increase of the antiviral activity of a2-macroglobulin and transferrine and a reduction ...
Biochemical studies on equine infectious anaemia. A description is given of an outbreak of equine infectious anaemia (E.I.A.) in Campania [at Naples and Aversa (Caserta)]; it was diagnosed by clinical, pathological and serological examinations (Coggins test). Using the serum of 45 horses with E.I.A. and 11 healthy horses (controls), numerous investigations were carried out on: enzymes, intrinsic coagulation factors, lipids and other substances. The results obtained were very interesting and show that in this disease there are significant increases in many enzymes (LDH, LAP, gamma-GT, CPK, PK and ALD) and copper. Insignificant increases were f...
The problem of testing horse kidneys for the presence of antibiotics at meat inspection: how to avoid a false positive reaction. When 33 horse kidneys were tested for the presence of inhibitory substances by the Bacillus subtilis BGA method at pH 8 and the Micrococcus luteus ATCC 9341 method, 24 were positive and 9 negative. The pH of the seeded M. luteus test medium changed from pH 6.6 before incubation to 8.7 after 24 hours incubation at 30 degrees C. When the same 33 kidneys were tested by the B. subtilis BGA method, medium pH 6, and 15 of them also by the M. luteus method using a medium buffered to pH 6, all were negative. The cadmium concentration of the 33 horse kidneys was found to be 70.17 +/- 81.28 mg/kg wet we...
Crystalline 3-phospho-d-glycerate kinase from horse muscle. 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...
Detection of immunologically active zones in equine growth hormone. Peptide fragments, obtained from equine growth hormone by cyanogen bromide cleavage and further chemical treatment, were isolated and identified. Their immunological reactivities were tested by hemagglutination and complement fixation methods using rabbit antisera against native hormone. Antigenic determinants were detected in the fragments comprising amino acid sequences 5-72 and 73-123, this last one being predominant. Fragment 124-178 had very low reactivity. Nitration of peptide 73-123 did not modify its immunological properties,but oxidation diminished them. Comparison of the antigenicity...
The influence of hepatic microsomal amidopyrine demethylase activity on halothane hepatotoxicity in the horse. The hepatotoxic effect of oral halothane in the horse is increased by pretreatment with phenobarbitone or DDT but not by chlorpromazine. Phenobarbitone and DDT increase the activity of hepatic amidopyrine N-demethylase but chlorpromazine does not. Carbon disulphide protects the liver of the horse against halothane.
Autoxidation in milk rich in linoleic acid. II. Modification of the initiation system and control of oxidation. Factors contributing to the initiation of lipid oxidation in cow's and mare's milk containing high levels of polyunsaturated fatty acids were studied. Addition of H2O2 just after milking, in slight excess of the stoichiometric amounts required to destroy ascorbic acid, delayed the development of oxidized flavours in cow's milk high in linoleic acid. Hydrogen peroxide treatment followed by the addition of alpha-or gamma-tocopherols prevented lipid oxidation in cow's milk even when 0.1 mg Cu/l milk was added. When used separately in the presence of Cu these treatments were ineffective as was but...
Steady-state enzyme kinetics of the pancreatic ribonucleases from five mannalian species. The kinetic parameters Km, k+2 and k+2/Km of the pancreatic ribonucleases (EC 3.1.4.22) from cow, giraffe, horse, rat and lesser rorqual have been determined, using 2',3'-cyclic cytidine monophosphate and 2',3'-cuclic uridine monophosphate as substrates. No large differences were found between the activities of the five enzymes. The relative differences between the activities of the five enzymes are mainly due to differences in the rates of hydrolysis and not to differences in the affinities for the substrates.
Isolation of kappa-casein-like proteins from milks of various species. Kappa-Casein-like proteins were isolated from the milks of cow, goat, reindeer, horse, rat, and rabbit. When treated with rennin, all of the isolated kappa-casein components yielded para-kappa-casein-like bands on gel electrophoresis. The rate of cleavage of these components with rennin was determined by measuring material soluble in trichloroacetic acid (macropeptide). The curves were characteristic of a limited, specific attack by rennin on these proteins. The goat and reindeer kappa-caseins were nearly as bovine kappa-casein, but the cleavage of horse, rat, and rabbit kappa-casein-like comp...