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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.
A re-evaluation of the D (+) xylose absorption test in the horse. The absorption of d-xylose forms the basis of a useful screening test in the investigation of small intestinal disorders in the horse. A comparison has been made of different assay methods and there was no significant difference between the results obtained with the parabromoaniline (PBA) method or the ferric chloride-orcinol (FCO) method. The orthotoluidine method was unsatisfactory. The anticoagulant agent did not affect the test. A dose of 0.5 g commercial grade xylose/kg body weight as a 10 per cent solution given by stomach tube, produced a peak plasma xylose level after 90 min and should...
Lipoproteins as substitutes for serum in Mycoplasma culture medium. Crude lipoprotein-containing fractions obtained from sera of three different animal species were tested, in combination with bovine serum in Mycoplasma pneumoniae culture medium. All sera yielded at least one lipoprotein-containing component which was considerably more effective in promoting mycoplasma growth than the unfractionated serum sample from which it was derived. The very low activity of certain whole-serum samples tested in this investigation suggests that toxic substances may be present in whole serum which are not contained in the lipoprotein preparations. The greatest activity app...
Identification of alpha1-lipoproteins in crossed immunoelectrophoresis. Evans Blue dye binds selectively, but with different avidities, to five major antigens in human serum. The anodic mobility of the antigen-dye complexes is greater than that of the antigens alone in crossed immunoelectrophoresis, which is of practical value for identification. We used this characteristic to show that in some human sera there is a population of alpha1-lipoprotein molecules that migrates electrophoretically in the beta-lipoprotein region, where in conventional zone electrophoresis it could be mistaken for beta-lipoprotein. We also demonstrate that horses, unlike rabbits, rarely m...
Colic in the horse. A clinical and clinical chemical study of 42 cases. 42 horses were examined. The physical signs with relation to circulatory insufficiency and the abdominal disease were registered following a two-phased examination procedure. Great prognostic value was found in the degree of circulatory insufficiency judged by pulse rate and character, filling of the jugular vein, skin temperature, colour of mucous membranes, capillary refill time, sweating, depression, skin turgor and degree of enophthalmus. In making a causal diagnosis the abdomen was examined for shape, tenderness, peristaltic sounds, gastric dilation by siphoning, abnormal rectal findings ...
Oxidation of (horse) hemoglobin by copper: an intermediate detected by electron spin resonance. The oxidation of horse hemoglobin by Cu(II) has been followed by the changes in the electron spin resonance spectra of copper. By stopped-flow and freeze-quenching techniques, it is shown that the second-order rate constant for the binding of Cu(II) to hemoglobin is greater than 5 X 10(5) mol-1 s-1 and the apparent first-order rate for the reduction of Cu(II) to Cu(I) is 0.051 s-1. It is also shown that the binding of Cu(II) to hemoglobin is followed by an alteration of the Cu(II) spectrum, decreasing the g values. This process has an apparent rate constant of 17 s-1 and presumably involves a ...
Isolation and partial characterization of prolactin from equine pituitary gland (hypophysis). Highly purified equine prolactin was prepared from equine pituitary glands (hypophysis) by serial extractions with water at pH 5.5, 0.1 M (NH4)2SO4 at pH 4.0, and 0.25 M (NH4)2SO4 at pH 5.5 to remove other hormones, and then finally with 70% ethanol at pH 9.3 to 10.0 to extract prolactin. Preliminary purification of the extract involved salting out other substances with 0.1% NaCl at pH 9.0. Prolactin was precipitated out by adding three times the volume of 95% ethanol at 4 C. This prolactin preparation had a biological potency of 24 IU/mg. Further purification by isoelectric focusing on a pH g...
Isolation and characterization of antibodies to Clostridium perfringens epsilon toxin from hyperimmune horse serum. Antibodies against epsilon toxin were isolated from hyperimmune horse serum by affinity chromatography. Purified epsilon prototoxin covalently bound to Affigel 202 was used as immunosorbent, and antibodies were eluted with 6.0 M guanidine chloride. In a single run 80 mg of antibody could be recovered from a 20 microliter column of immunosorbent. The antibody was shown to belong to the IgG(T) class of immunoglobulins.
Occurrence of Leu-Lys-bradykinin and histidine-rich peptide in high-molecular-weight kininogen isolated from horse plasma. On incubation of purified horse plasma high-molecular-weight kininogen with purified plasma kallikrein, three new peptides, named fragment 1.2, fragment 1 and fragment 2, were released, in addition to the vasopeptide, bradykinin. Fragment 2 contained an extremely high level of histidine, in which eleven residues out of the total 48 residues were characterized. Thus the result proves the existence of the histidine-rich region in horse high-molecular-weight kininogen, which is similar to the region previously identified in bovine high-molecular-weight kininogen. Moreover, we have identified a ne...
Proliferation and morphology of chick embryo cells cultured in the presence of horse serum and hemoglobin. We have shown previously that hemoglobin greatly stimulates chick embryo cell proliferation in Eagle's minimal essential medium supplemented with horse serum. In the present study we compared the effects of horse serum plus 10 micrometers hemoglobin to those of fetal bovine serum on subcultures of chick embryo cells serially propagated at high cell densities. The cells became elongated in the presence of fetal bovine serum and their rate of proliferation progressively decreased, whereas they became polygonal in the presence of horse serum plus hemoglobin and proliferated well in successive cel...
Cannulation of the equine oviduct and chemical analysis of oviduct fluid. Siliconized rubber tubes were used to cannulate one oviduct in 7 mares, and secretions were collected in a polycarbonate container located externally, in the region of the left paralumbar fossa. Secretion rates were recorded daily during the estrous cycle. Concentrations of calcium, magnesium, sodium, potassium, inorganic phosphorus and glucose were determined in the oviduct fluids secreted throughout the estrous cycle. Secretion rates were greatest during estrus (days 1-9), with a significant decrease (P<.01) noted during nonestrus (days 10-21). Concentrations of all constitutents measured...
Adrenal-testis interaction in the stallion. The authors describe the short and long term effects of synthetic adrenocorticotrophin and of cortisol on peripheral plasma testosterone concentrations in 2 stallions. A single injection of either hormone temporarily raised plasma testosterone concentrations but repeated injection (twice daily for 5 days) depressed plasma testosterone concentrations. Cessation of treatment was followed by a rise in plasma testosterone to concentrations higher than those in the pretreatment period. These findings are briefly discussed.
Effect of exercise, phenylbutazone, and furosemide on the plasma renin activity and angiotensin I in horses. Circulating concentrations of angiotensin I and plasma renin activity (PRA) were determined in 45 Thoroughbreds before prerace medication (at rest), 1 to 1 1/2 hours before racing but after prerace medication (prerace), within 15 minutes after racing (immediately postrace), and between 1 to 2 hours after racing. Angiotensin I was measured by radioimmunoassay, and PRA was determined by the rate of generation of angiotensin I in plasma incubated at 37 C. Irrespective of prerace medication, there was a marked increase in angiotensin I (0.478 +/- 0.034 to 0.848 +/- 0.051 ng/ml) and PRA (0.191 +/- ...
Purification of the subunit Clq from the first component of equine complement. Initial separation and concentration of Clq from fresh, normal equine serum was accomplished by precipitation in 0.02 M acetate buffer, pH 5.5, at 4 degrees for 24 h. The re-dissolved precipitate was clarified by centrifugation at 80,000 g for 1 h and then dialysed against Tris-HCl buffer (0.05 M, pH 8.0) containing 10-3 M EDTA. The clarified dialysate remained biologically active at 5 degrees for at least 4 weeks. Biological activity of equine Clq was determined by assay of its ability to agglutinate sensitized sheep erythrocytes (EA). Following ammonium sulphate fractionation, Sepharose 4B g...
In vitro of adenosine on lymphocytes and erythrocytes from horses with combined immunodeficiency. The effect of adenosine on the mitogenic response of peripheral blood lymphocytes (PBL) and on the nucleotide pools of erythrocytes from normal horses, horses heterozygous for the combined immunodeficiency (CID) trait (carriers), and foals with CID was studied. When PBL from normal, carrier, and CID horses were stimulated by phytohemagglutinin (PHA), concanavalin A, or pokeweed mitogen, [3H]thymidine uptake was inhibited by adenosine (0.1 microM) to 1.0 mM) in a dose-dependent manner. Adenosine (100 microM) mediated inhibition of [3H]thymidine uptake was prevented in both normal and carrier ho...
Immunochemical studies on beta-lactoglobulins. precipitin reactions of sow’s and mare’s mammary secretions against anti – bovine beta – lactoglobulin antiserum. By double diffusion in agarose gel, in well defined experimental conditions, cross reactions were observed between porcine beta-lactoglobulins and anti-bovine beta-lactoglobulin antisera. The immunological reactivity between these beta-lactoglobulins from a monogastric and the ruminant anti beta-lactoglobulin antiserum thus implies a certain degree of similarity between the monomeric beta-lactoglobulins examined and the dimeric of the ruminants. With the same antisera it also proved possible to demonstrate the presence of beta-lactoglobulins in the mammary secretions of another monogastric, na...
Intracecal endotoxin and lactate during the onset of equine laminitis: a preliminary report. Cecal fluid from two adult horses was assayed by the limulus amebocyte lysate system for endotoxin before and after carbohydrate overload of the gastrointestinal tract. There were increases in cecal fluid endotoxin concentrations at the 3-, 6-, and 12-hour samplings when compared with base-line values. Concomitant cecal fluid lactate concentrations and pH values increased and decreased, respectively. Both horses subsequently developed clinical signs of acute laminitis.
Studies related to the metabolism of anabolic steroids in the horse: testosterone. 1. After intramuscular administration of [4-14C]testosterone to two cross-bred gelded horses, 45% of the radioactivity was excreted in urine in 96 h. Small amounts of urinary activity could still be detected at 200 h. 2. Neutral metabolites obtained after both enzyme and acid hydrolysis of urine samples have been investigated by g.l.c.-mass spectrometry. 3. 5 alpha-Androstane-3 beta, 17 alpha-diol was found only in the enzyme-hydrolysable extract and testosterone only in the acid-hydrolysable extract. 5 alpha-Androstane-3 beta, 17 beta-diol and 3 beta-hydroxy-5 alpha-androstan-17-one were foun...
Seasonal relationship between pineal hydroxyindole-O-methyltransferase (HIOMT) activity and reproductive status in the pony. Pony pineal glands and female reproductive tracts were collected monthly for 1 year from
a local slaughterhouse. Pineal gland weights did not change significantly throughout the year.
Pineal gland tissue homogenates were assayed for hydroxyindole-O-methyltransferase
(HIOMT) activity with N-acetylserotonin as the primary substrate. The greatest HIOMT
activity was obtained with N-acetylserotonin as substrate. but three other related S-OH
indole substrates (5-hydroxytryptophol, serotonin. and 5-hydroxy-2-methylindole) were also
methylated. HIOMT activity with all substrates was highest duri...
Haptoglobin in the serum of thoroughbreds in training. A method is described for the measurement of haptoglobin in equine serum using the peroxidase activity of the haemoglobin-haptoglobin complex. The problems of interference with Fe2+ and Fe3+ ions are described. Normal values for haptoglobin in 629 blood samples from thoroughbreds in training are presented showing a log normal distribution with a 5 per cent to 95 per cent range of 0.42 to 1.7 g/litre. There was no consistent alteration in haptoglobin concentration throughout the season in spite of a change in red cell size and total bilirubin concentration. It is concluded that the measurement ...
Chemical mediators of immediate hypersensitivity reactions. The investigation of the mast cell-basophil products has progressed from studies directed solely at implicating histamine or serotonin in allergic diseases to molecular definitions of pathways to target cell activation and mediator release. In addition, within the last several years the detection and molecular characterization of the many other mediators of immediate hypersensitivity have begun. This area should continue to prove a fruitful arena in the future. Identification of the physiologic importance of these mediators in the heaves syndrome or other potential equine allergic syndromes ma...
The effect of binding ions on the oxidation of horse heart ferrocytochrome c. The research explores how different binding ions affect the oxidation speed of horse heart ferrocytochrome c, a protein, by potassium ferricyanide at a constant ionic strength. Studying the Ion Effect […]
Adrenal gland function in the horse: effects of cosyntropin (synthetic) and corticotropin (natural) stimulation. The plasma concentration of hydrocortisone was determined in mares given either cosyntropin (100 IU, given IV) or corticotropin (200 IU, given IM). Plasma hydrocortisone concentrations of the mares treated with cosyntropin increased by 46%, 57% and 80% at 30, 60, and 120 minutes, respectively, when compared with base-line values; these values returned to base line at 240 minutes. In mares treated with corticotropin, mean plasma hydrocortisone concentrations increased by 42%, 143%, 101% and 155% at 30, 60, 120, and 240 minutes, respectively, when compared with base-line values. Differences in t...
