Liver function in horses encompasses a range of physiological processes essential for maintaining homeostasis. The liver is responsible for various metabolic, detoxification, and synthetic activities, including the metabolism of carbohydrates, proteins, and fats, as well as the detoxification of endogenous and exogenous substances. It also synthesizes proteins such as albumin and clotting factors, and produces bile necessary for digestion. Liver function can be assessed through biochemical tests that measure enzyme activities and metabolite levels in the blood. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, assessment, and clinical implications of liver function in equine health.
Schmoldt A, Benthe HF, Haberland G, Tarentino AL, Maley F, Berkmen YM, Lande A, Fine JM, Lambin P, Derycke C, North ML, Chataing B, Goudemand M.The chest roentgenographic findings in Takayasu's arteritis include widening of the ascending aorta, contour irregularities of the descending aorta, arotic calcifications, pulmonary arterial changes, rib notching, and hilar lymphadenopathy. The single most important diagnostic sign is a segmental calcification outlining a localized or diffuse narrowing of the aorta. The other signs may be suspicious or suggestive, but the diagnostic accuracy increases when several findings are present simultaneously. A routine screening of monoclonal gammopathies (M.G.) was performed in the serum from 36, 015 ...
Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Marshall WL, Stoian M, Andrews WR.It has been shown that for the reaction catalyzed by "biodegradative" L-threonine dehydratase from E. coli strains K-12 and 980 in 0.5 M phosphate-carbonate buffer, pH 8.4 and pH 9.5, the plots of initial reaction rate (v) versus the initial substrate concentration ([S]0 are characterized by several inflection points, i. e. an intermediate plateau. The plot of v versus the allosteric activator (AMP) concentration have very complicated shapes: there are several inflection points, and also the maximum at L-threonine concentration equal to 3-10(2) and 5-10(-2) M. High AMP concentrations inhibit t...
Schmoldt A, Benthe HF, Haberland G, Jallon JM, Risler Y, Iwatsubo M, Karuzina II, Bachmanova GI, Kuznetsova GP, Izotov MV, Archakov AI, Kröger H....It has been found that NADPH-dependent hydroxylation of dimethylaniline, aniline, p- and o-nitroanisol and lipid peroxidation is inhibited by the tyrosine-copper (II) complex (low molecular weight analog of superoxide dismutase), which is indicative of a possibility of superoxide radicals formation in these reactions. The inhibition of the above-mentioned reactions with Tyr2-Cu2+ is less pronounced or absent, if cumole hydroperoxide is used as cosubstrate instead of NADPH. Differences in the Tyr2-Cu2+ complex effects on the cumule hydroperoxide-dependent xenobiotics hydroxylation and lipid per...
Slocombe JO, McCraw BM.Four pony foals were inoculated with Strongylus edentatus infective larvae and on days 3 and 4 postinfection two of the ponies were treated with thiabendazole, each at the rate of 440 mg/kg of body weight. Total circulating eosinophil counts in untreated ponies increased to over 1700 per cu mm after the second week postinfection. In the treated ponies as well as in an uninfected untreated pony eosinophil counts did not increase beyond 100 per cu mm. At necropsy on day 35 postinfection the cecum, colon and omentum of treated ponies were normal and few tracks were present on the surface of the l...
Inkerman PA, Scott K, Runnegar MT, Hamilton SE, Bennett EA, Zerner B.Chicken, sheep, and horse liver carboxylesterases have been purified by procedures involving ammonium sulfate fractionation, ion-exchange chromatography and gel filtration on Sephadex. The actual yields of the procedures described were as follows: chicken, 1 g from 2 kg of liver powder (chloroform-acetone); sheep, 200 mg from 400 g of powder (chloroform-acetone); horse, 230 mg from 800 g of powder (acetone). The purified enzymes are free of non-carboxyl-esterase protein as shown by gel electrophoresis, although they do contain electrophoretic variants. The equivalent weight of the chicken enzy...
Hinson JA, Neal RA.The kinetics of the horse liver alcohol dehydrogenase (alcohol: NAD+ oxidoreductase EC 1.1.1.1) catalyzed metabolism of octanol and octanal to octanoic acid have been examined. On incubation of octanol with horse liver alcohol dehydrogenase in the presence of NAD+, NADH as well as octanal and octanoic acid were seen as the initial products. However, on continued incubation, the octanal concentration progressively decreased to where only negligible quantities were present in the incubation after 10 min. The production of NADH was biphasic. An initial phase was followed in about 2 min with a slo...
Harrington DD.Spontaneous Tyzzer's disease is described in quarter horse foals which died suddenly with no clinical history of apparent illness. Significant gross findings included icterus, focal paletan areas in the liver and catarrhal entercolitis. Focal dark red lesions were present in the small intestine of one foal, and the mesenteric lymph nodes of another were enlarged and hyperemic. Histopathologically, the liver showed multiple discrete and confluent foci of necrosis, fatty change, sinusoid congestion and haemorrhage. Bundles of intracytoplasmic bacilli were demonstrated in hepatocytes at the margi...
Wasyl Z.1. Horse liver acid phosphatase was separated into two partially purified fractions differing in molecular weight (enzyme I about 100 00, enzyme II about 25 000). 2. Enzyme I was separated into several subfractions by DEAE-cellulose chromatography and isoelectric focusing. 3. Molecular weight, sedimentation coefficient and effective molecular radii were determined for acid phosphatases I and II by gel filtration and density-gradient centrifugation.
Hooper PT.Severe spongy degeneration of the central nervous system (CNS) was seen in 11 cattle, 19 sheep, 4 pigs and 1 goat, associated with a variety of hepatic diseases, particularly those caused by hepatotoxic pyrrolizidine alkaloids. It was also seen in a milder form in 2 of 8 horses examined, 1 dog of 5 dogs examined, and in 1 rabbit only of a large number of laboratory animals examined. This paper reports results of experiments which confirmed initially that the CNS disease cold be caused by pyrrolizidine alkaloid intoxication. This was done by poisoning lambs with lasiocarpine. As the disease was...
McCraw BM, Slocombe JO.Pony foals inoculated with infective Strongylus edentatus larvae were monitored for clinical signs and selected blood changes and were examined at necropsy from two to 56 days postinfection. Larvae penetrated the intestine and reached the liver intravenously before 40 hours postinfection. Occasional thrombi and larval tracks associated with the intima of cecal and colic veins suggested aberrant paths. Larvae in the liver doubled in width between seven and 15 days postinfection and a sudden increment in circulating eosinophils occurred between 11 and 15 days. These changes were probably associa...
Stover SM, Steffey EP, Dybdal NO, Franti CE.Five horses were anesthetized similarly by use of xylazine, guaifenesin, thiamylal sodium, and halothane in oxygen on 3 consecutive days, and minor surgical procedures were performed. For 1 to 10 days after the last anesthetic exposure, clinical, hematologic, and serum biochemical features were monitored, and after necropsy, histologic examination of major organ tissues was performed. Predominant hematologic changes from base-line values included leukocytosis (maximal at 27 hours, 10,500 +/- 1,750 cells/microliter), neutrophilia (maximal at 51 hours, 7,485 +/- 1,719 cells/microliter), and lymp...
Nation PN.Over sixteen years, 49 horses were diagnosed by Alberta Agriculture Animal Health laboratories as having "alsike clover poisoning". There was a distinct northwestern distribution of cases, the majority coming from the Peace River district. This distribution is opposite to that of the Alberta horse population, but coincides with areas of alsike clover cultivation. Cases could be divided into chronic or nervous clinical presentations, as described by Schofield. Tissues from 45 animals were retrieved and examined microscopically. Significant histological lesions were confined to the liver and con...
Perkins G, Ainsworth DM, Erb HN, Del Piero F, Miller M, Wilkins PA, Palmer J, Frazer M.A retrospective multicentre study comparing historical, clinical, haematological, acid-base and biochemical findings of foals with Equine herpesvirus-1 (EHV-1) infection, septicaemia or prematurity was performed to determine if early diagnosis of EHV-1 foals was possible. Fifty-three foals were studied and were assigned to one of 2 groups: herpes positive (n = 14) or herpes negative (n = 39). The latter group included 20 septic, 11 premature, and 8 premature and septic foals. The presence of herpes antigen was confirmed by immunoperoxidase histochemical staining of tissues from necropsied foal...
Kraft W.Clinical symptoms of hepatopathies are not specific and must be verified by further investigation. Laboratory diagnosis is a very useful method to decide if liver disease is present or not. In individual cases laboratory methods can give hints as to the aetiology of the illness. If necessary, biopsy, angiography or/and cholecystography can be carried out for further clarification of the diagnosis.
Mullaney TP, Brown CM, Watson GL, Brandt LA.An apparently new and emerging fatal hepatic disease affecting foals is described. Characteristics included evidence of hepatic failure, marked biliary hyperplasia, hepatocellular necrosis and occasionally fibrosis. Generally, the features of the disease appear to differ markedly from other hepatic diseases of neonatal foals.
Engelking LR, Paradis MR.This article addresses clinical problems that present in equine liver disease. It also discusses the variety of laboratory tests available to the clinician that can differentiate the type and degree of liver dysfunction. This is followed by a more specific discussion regarding unique features of equine bilirubin and bile acid metabolism.
Simpson JW, Else RW.Methods are described for the endoscopic examination and biopsy of the gastrointestinal tract and liver of the dog, cat, ox and horse. The results of the examination of 41 biopsy samples are shown, followed by a discussion of the value of biopsy in the diagnosis of diseases of the digestive tract.
Scandurra R, Politi L, Santoro L, Consalvi V.Horse liver phosphopantothenoylcysteine decarboxylase (EC 4.1.1.36) incorporates nonexchangeable tritium from borotritide with a decrease of the activity. Substrate prevents both tritium incorporation and the decrease in activity. Acid and base hydrolysis of the tritiated protein releases labeled lactate identified by high-voltage paper electrophoresis, paper chromatography and silicic acid chromatography. These results indicate the presence of pyruvate covalently bound through an ester linkage to phosphopantothenoylcysteine decarboxylase which is then another example of a mammalian enzyme in ...
Leung GN, Tang FP, Wan TS, Wong CH, Lam KK, Stewart BD.This paper describes the application of gas chromatography-mass spectrometry (GC-MS) for in vitro and in vivo studies of 6-OXO in horses, with a special aim to identify the most appropriate target metabolite to be monitored for controlling the administration of 6-OXO in racehorses. In vitro studies of 6-OXO were performed using horse liver microsomes. The major biotransformation observed was reduction of one keto group at the C3 or C6 positions. Three in vitro metabolites, namely 6alpha-hydroxyandrost-4-ene-3,17-dione (M1), 3alpha-hydroxyandrost-4-ene-6,17-dione (M2a) and 3beta-hydroxyandrost-...
Lotstra RJ, van den Broek J, Power T, Marr CM, Wijnberg ID.Atrial fibrillation is a common equine arrhythmia. Quinidine alone, or with digoxin are common treatments. Studies on outcome in Warmblood populations in which duration of the AF is often unknown are limited. Objective: To identify the factors that are associated with the success of full treatment cardioversion with oral medication, and establish whether there are differences in these factors between institutions. Methods: Retrospective case series using patient records of Equine University Clinic of Utrecht University and Rossdales Equine Hospital, Newmarket. Methods: Forty-nine horses treate...
McGavin MD, Knake R.A 35-kg Duroc pig died 3 days after eating a ration containing aflatoxin B1, B2, G1, and G2. It had hemorrhagic enteritis and extensive midzonal necrosis in the liver. A 13-year-old Quarterhorse that died 2 days after eating moldy hay had hemorrhagic enteritis, fatty degeneration of the myocardium and renal tubules, and extensive total midzonal necrosis of the liver.
Richards KS, Ilderton E, Yardley HJ.Lipids extracted from the laminated layers of horse liver and lung hydatids, including a daughter liver cyst, were analysed using TLC. No differences in lipid composition was detected in 11 liver cysts, whether from the same or different livers, and di- and triacylglycerols, cholesterol, wax and steryl esters, oleic acid, sphingomyelin, phosphatidyl choline, phosphatidyl inositol and ceramide hexosides were detected. The daughter cyst differed from its "parent" cyst in lacking diacylglycerols and wax and steryl esters. The lung cyst differed from the liver cysts in that cholesterol, wax and st...
Perryman LE, Liu IK.Nine foals with combined immunodeficiency were given hepatic and thymus cells from 68- to 110-day-old (gestational age) fetuses or peripheral blood lymphocytes from nonrelated horses. Clinical signs and lesions consistent with graft vs host reaction were observed in eight of the foals. Diarrhea was observed in these 8 foals, and ulcerative dermatitis, stomatitis, or glossitis was detected in 6 of the 8 foals. Histopathologic changes consisting of necrosis and lymphocyte infiltration were observed in liver, skin, alimentary tract, and less frequently in lymphoid tissues. Changes in complete blo...
Charleston WA, McKenna PB.A general review of the epidemiology, significance and control of nematode parasitism of sheep, goats, cattle and deer in New Zealand, the emergence of anthelmintic resistance and its effects, and the search for parasite control strategies that reduce reliance on anthelmintic use, is provided. The research that has formed the basis for present levels of understanding of this complex and important topic is summarised and sources of further information are indicated. Aspects of nematode infections of horses, pigs, dogs and cats, and the history of the liver fluke, Fasciola hepatica, in New Zeala...
Skrabalak DS, Maylin GA.Dexamethasone and a metabolite, 9-fluoro-16α-methyl-6β, 11β, 16β-trihydroxy-1, 4-androstadiene-3, 17-dione, were detected in the urine of horses injected parenterally with the parent drug. The structure of the metabolite was elucidated by thin-layer chromatography, infrared spectroscopy, mass spectroscopy and nuclear magnetic resonance spectroscopy.
Wanstrath MA, Bauck AG, Smith AD, Freeman DE.To assess the safety and efficacy of a method for digitally enlarging the caudal aspect of the epiploic foramen (EF). Methods: Healthy horses and clinical cases of EF entrapment (EFE). Methods: Fourteen healthy horses and three clinical cases. Methods: Through a ventral midline celiotomy under general anesthesia, the EF was enlarged by digital separation of the caudal attachments of the caudate lobe of the liver from right dorsal colon, right kidney, gastropancreatic fold, and pancreas. Healthy horses were euthanized under anesthesia, and the enlarged EF was measured at necropsy. Results: The ...
Georgadze IA, Nozadze ZM.The hyperimmunization of horses with large doses of tetanus toxoid is accompanied by an increase in the levels of both specific antitoxic antibodies and autoantibodies to the tissue antigens of the liver, the spleen, the heart. The reverse relationship between the level of autoantibodies and the titer of antitoxin has been established. The authors suggest that the synthesis of autoantibodies is stimulated by the presence of antigen-antibody immune complexes in the circulating blood, as well as by the action of exo- and endopolyclonal stimulators.
