Steroids in horses refer to a class of compounds that include both naturally occurring and synthetic substances designed to mimic the effects of hormones such as cortisol and testosterone. These compounds can influence a wide range of physiological processes, including metabolism, immune response, and muscle growth. In equine medicine, steroids are sometimes used therapeutically to manage conditions such as inflammation, allergies, and certain musculoskeletal disorders. However, their use in competitive sports is often regulated due to potential performance-enhancing effects. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacology, therapeutic applications, and regulatory aspects of steroid use in equine health and athletic performance.
Menéndez MI, Phelps MA, Hothem EA, Bertone AL.To determine the pharmacokinetics of methylprednisolone (MP) and the relationship between MP and hydrocortisone (HYD) concentrations in plasma and urine after intra-articular (IA) administration of 100 or 200 mg of MP acetate (MPA) to horses. Methods: Five 3-year-old Thoroughbred mares. Methods: Horses exercised on a treadmill 3 times/wk during the study. Horses received 100 mg of MPA IA, then 8 weeks later received 200 mg of MPA IA. Plasma and urine samples were obtained at various times for 8 weeks after horses received each dose of MPA; concentrations of MP and HYD were determined. Pharmaco...
Soma LR, Uboh CE, Liu Y, Li X, Robinson MA, Boston RC, Colahan PT.This study investigated and compared the pharmacokinetics of intra-articular (IA) administration of dexamethasone sodium phosphate (DSP) into three equine joints, femoropatellar (IAS), radiocarpal (IAC), and metacarpophalangeal (IAF), and the intramuscular (IM), oral (PO) and intravenous (IV) administrations. No significant differences in the pharmacokinetic estimates between the three joints were observed with the exception of maximum concentration (Cmax ) and time to maximum concentration (Tmax ). Median (range) Cmax for the IAC, IAF, and IAS were 16.9 (14.6-35.4), 23.4 (13.5-73.0), and 46.9...
Gray BP, Biddle S, Pearce CM, Hillyer L.Fluticasone propionate (FP) is an anti-inflammatory agent with topical and inhaled applications commonly used in the treatment of asthma in steroid-dependent individuals. The drug is used in racehorses to treat Inflammatory Airway Disease; this work was performed in order to advise on its use and detect potential misuse close to racing. Methods were developed for the extraction and analysis of FP from horse plasma and a carboxylic acid metabolite (FP-17βCOOH) from horse urine. The methods utilize ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in ...
Fidani M, Pompa G, Mungiguerra F, Casati A, Fracchiolla ML, Arioli F.After the detection of low concentrations of prednisolone in racehorse urine samples collected at Italian racetracks, a study was initiated to investigate the accuracy of the analytical protocol used and the possible endogenous origin of detected prednisolone. Methods: Multiple reaction monitoring (MRM) MS(2) acquisition with a triple quadrupole (n = 780) and full scan MS(2) and MS(3) (n = 180) acquisition with a linear ion trap were checked. As a further confirmation, ten urine samples were analysed by high-resolution mass spectrometry (HRMS). Results: The study showed the difficulty of ident...
Herrera-Luna CV, Budik S, Aurich C.Glucocorticoids (GCs) are important mediators of the stress response and have been implicated in the function and regulation of testicular functions in different species. In many tissues, intracellular glucocorticoid activity is controlled by either or both of the two known isoforms of 11β-hydroxysteroid dehydrogenase (11βHSD) type 1 and 2, which interconvert active and inactive GCs. Little is known about the effects of stress on fertility in the equine species. The main objective of the present study was to investigate the expression of receptors for GCs and adrenocorticotropic hormone [ACT...
Wong CH, Leung DK, Tang FP, Wong JK, Yu NH, Wan TS.Liquid chromatography/mass spectrometry (LC/MS) has been successfully applied to the detection of anabolic steroids in biological samples. However, the sensitive detection of saturated hydroxysteroids, such as androstanediols, by electrospray ionisation (ESI) is difficult because of their poor ability to ionise. In view of this, chemical derivatisation has been used to enhance the detection sensitivity of hydroxysteroids by LC/MS. This paper describes the development of a sensitive ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) method for the screening of a...
Soma LR, Uboh CE, You Y, Guan F, Boston RC.To compare pharmacokinetics of triamcinolone acetonide (TA) following i.v., intra-articular (i.a.), and i.m. administration and determine its effect on plasma concentrations of hydrocortisone and cortisone. Methods: 6 Thoroughbreds. Methods: TA (0.04 mg/kg) was administered i.v., i.m., or i.a., and plasma TA, hydrocortisone, and cortisone concentrations were determined. Results: I.v. administration of TA was fitted to a 2-compartment model. Median distribution half-life was 0.50 hours (range, 0.24 to 0.67 hours); elimination half-life was 6.1 hours (range, 5.0 to 6.4 hours). Transfer half-life...
van der Geize R, Grommen AW, Hessels GI, Jacobs AA, Dijkhuizen L.Rhodococcus equi causes fatal pyogranulomatous pneumonia in foals and immunocompromised animals and humans. Despite its importance, there is currently no effective vaccine against the disease. The actinobacteria R. equi and the human pathogen Mycobacterium tuberculosis are related, and both cause pulmonary diseases. Recently, we have shown that essential steps in the cholesterol catabolic pathway are involved in the pathogenicity of M. tuberculosis. Bioinformatic analysis revealed the presence of a similar cholesterol catabolic gene cluster in R. equi. Orthologs of predicted M. tuberculosis vi...
You Y, Uboh CE, Soma LR, Guan F, Li X, Liu Y, Rudy JA, Chen J, Tsang D.The potential for using testosterone and nandrolone esters in racehorses to boost the biological concentrations of these steroids and enhance athletic performance is very compelling and should be seriously considered in formulating regulatory policies for doping control. In order to regulate the use of these esters in racehorses, a sensitive and validated method is needed. In this paper, we report such a method for simultaneous separation, screening, quantification and confirmation of 16 testosterone and nandrolone esters in equine plasma by ultra high performance liquid chromatography-tandem ...
Soma LR, Uboh CE, You Y, Guan F, McDonnell S.Pennsylvania (PA) State Racing Commissions regulate the endogenous androgenic steroid, testosterone (TES), in racing intact males (RIM) by quantification of TES in post-race samples. Post-race plasma samples (2209) collected between March 2008 and November 2010 were analyzed for TES, nandrolone (NAN), and other anabolic steroids (ABS). Of the 2209 plasma samples, 2098 had quantifiable TES ≥ 25 pg/mL. Plasma (mean ± SD) concentrations of TES and NAN in RIM were 329.2 ± 266.4 and 96.0 ± 67.8 pg/mL, respectively. Only 64.6% of RIM had quantifiable concentration of NAN, and there was no relat...
Knobbe MG, Maenhoudt C, Turner RM, McDonnell SM.2 Standardbred racehorses that had been winning races while competing as mares underwent postrace drug testing and had serum testosterone concentrations above the acceptable limit for female racehorses. Results: Initial physical examinations by the referring veterinarian revealed ambiguous external genitalia and suspected intra-abdominally located testes leading to a preliminary diagnosis of male pseudohermaphroditism. Horses were referred for further evaluation of sex. Physical examination of the external genitalia confirmed the findings of the referring veterinarian. Transrectal palpation an...
Clarke A, Scarth J, Teale P, Pearce C, Hillyer L.Detection of androgenic-anabolic steroid abuse in equine sports requires knowledge of the drug's metabolism in order to target appropriate metabolites, especially where urine is the matrix of choice. Studying 'designer' steroid metabolism is problematic since it is difficult to obtain ethical approval for in vivo metabolism studies due to a lack of toxicological data. In this study, the equine in vitro metabolism of eight steroids available for purchase on the Internet is reported; including androsta-1,4,6-triene-3,17-dione, 4-chloro,17α-methyl-androsta-1,4-diene-3,17β-diol, estra-4,9-diene-...
Almeida J, Conley AJ, Mathewson L, Ball BA.In the mammalian testis, Leydig cells are primarily responsible for steroidogenesis. In adult stallions, the major endocrine products of Leydig cells include testosterone and estrogens. 3β-hydroxysteroid dehydrogenase/Δ(5)-Δ(4)-isomerase (3βHSD) and 17α-hydroxylase/17,20-lyase (P450c17) are two key steroidogenic enzymes that regulate testosterone synthesis. Androgens produced by P450c17 serve as substrate for estrogen synthesis. The aim of this study was to investigate localization of the steroidogenic enzymes P450c17, 3βHSD, and P450arom and to determine changes in expression during dev...
Teale P, Houghton E.The fight against doping in sport using analytical chemistry is a mature area with a history of approximately 100 years in horseracing. In common with human sport, anabolic/androgenic steroids (AASs) are an important group of potential doping agents. Particular issues with their detection are extensive metabolism including both phase I and phase II. A number of the common AASs are also endogenous to the equine. A further issue is the large number of synthetic steroids produced as pharmaceutical products or as 'designer' drugs intended to avoid detection or for the human supplement market. An u...
Casella S, Giannetto C, Giudice E, Piccione G.The objective of the present study was to evaluate the platelet response to different workload in athletic horse and the influence of hydrocortisone on this response. For this purpose, six Sella Italiana gelding athletic horses, ranging in age from 8 to 10 years and clinically healthy, were subjected to four different exercises: horse-walker, treadmill, obstacle course of 1.00 m and obstacle course of 1.25 m. From all the horses, citrated plasma samples were collected at rest, immediately after exercise and 30 min after the end of the exercise to assess the maximum degree of platelet aggregati...
Spiess BM.Equine recurrent uveitis (ERU) has always been and still is an important disease with a significant impact on the horse industry in Europe, with a prevalence of 8-10%. The need to understand and manage the disease has spurred the development of veterinary ophthalmology in general, although the aetiology of the disease remains the subject of intense discussion. It is most probably an autoimmune disease triggered, at least in Europe, in the majority of cases by Leptospira spp. The therapy of ERU has evolved over the centuries from various methods of bloodletting to rational medical therapy using...
Liu Y, Uboh CE, Soma LR, Li X, Guan F, You Y, Rudy JA, Chen JW.In 2008, Pennsylvania (PA) became the first State in the USA to ban and enforce the ban on the use of anabolic and androgenic steroids (AAS) in equine athletes by using plasma for analysis. To enforce the ban, a rapid and high-throughput method for analysis of 60 AAS in equine plasma was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analytes were recovered from plasma by liquid-liquid extraction (LLE) using methyl tert-butyl ether, separated on a reversed-phase C₁₈ column and analyzed by electrospray ionization mass spectrometry. Multiple-reaction monitoring (MRM)...
Guan F, Uboh CE, Soma LR, You Y, Liu Y, Li X.Anabolic and androgenic steroids (AASs) are synthetic substances related to the primary male sex hormone, testosterone. AASs can be abused in both human and equine sports and, thus, are banned by the International Olympic Committee and the Association of Racing Commissioners International (ARCI). Enforcement of the ban on the use of AASs in racehorses during competition requires a defensible and robust method of analysis. To address this requirement, a high-throughput ultra high-performance liquid chromatography-mass spectrometric (UHPLC-MS) method was developed for the detection, quantificati...
Haffner JC, Fecteau KA, Eiler H, Tserendorj T, Hoffman RM, Oliver JW.Traditionally, analysis of blood cortisol alone has been used to evaluate adrenal function. Currently, multisteroid analyses are considered more informative than analysis of a single hormone to assess adrenal function. The objective of the present research was to create a database for steroid reference values for domestic Mongolian horses. Seven adrenal steroid levels were determined in the blood of 18 colts, 34 stallions, 25 geldings, 17 fillies, and 29 mares. Results were as follows (lowest and highest group median, in nanograms per milliliter): progesterone: <0.030 (fillies), 4.30 (mares), ...
Bailey SR.A direct causal association between corticosteroid use and laminitis has yet to be proven scientifically, and there have been few studies specifically addressing this aspect. New evidence, however, is improving the understanding of the causes of laminitis, particularly related to endocrine factors. The focus of this article is discussing the circumstances under which steroids might cause this condition.
Piper T, Geyer H, Gougoulidis V, Flenker U, Schänzer W.Boldenone (androsta-1,4-dien-17beta-ol-3-one, Bo) is an anabolic steroid known to have been used in cattle breeding or equine sport as a doping agent for many years. Although not clinically approved for human application, Bo or its main metabolite 5beta-androst-1-en-17beta-ol-3-one (BM1) were detected in several doping control samples. For more than 15 years the possibility of endogenous Bo production in human beings has been discussed. This is a challenging issue for doping control laboratories as Bo belongs to the list of prohibited substances of the World Anti-Doping Agency and therefore th...
Flauger B, Krueger K, Gerhards H, Möstl E.Glucocorticoids or their metabolites can be measured in several body fluids or excreta, including plasma, saliva, urine and faeces. In recent years the measurement of glucocorticoid metabolites (GCMs) in faeces has gained increasing attention, because of its suitability for wild populations. In horses, however, the group-specific enzyme immunoassay described so far has a limited practicability due to its complex extraction procedure. Therefore, we tested the applicability of other enzyme immunoassays for glucocorticoid metabolites. The present study clearly proved that an enzyme immunoassay (E...
Raeside JI, Christie HL, Waelchli RO, Betteridge KJ.Estrogen production by the trophoblast is considered important in early equine pregnancy and leads to high concentrations in yolk-sac (Y-S) fluid. The embryo proper is a potential site for their action. We examined estrogen metabolism in the embryo proper because some actions of estrogens are derived from locally formed metabolites. The embryo proper, as well as separated extraembryonic tissues, of conceptuses collected about day 25 of pregnancy, were incubated with (3)[H]-estrone (E(1)) and (3)[H]-estradiol (E(2)). Steroids were recovered from media by solid-phase extraction and eluted separa...
Abraham G, Allersmeier M, Gottschalk J, Schusser GF, Hoppen HO, Ungemach FR.There are no data available regarding the systemic (adverse) effects which might be induced by topical/dermal glucocorticoids (GCs) application in the horse. Besides their widespread use for the treatment of a variety of peripheral inflammatory disorders such as atopic dermatitis, eczemas or arthritis in the horse, their surreptitious application has become a concern in doping cases in competition/performance horses. Assessing both basal and ACTH-stimulated plasma cortisol as well as basal ACTH concentrations following application of dexamethsone-containing dermal ointment is necessary to dete...
Zhang N, Ding S, Kolbanovskiy A, Shastry A, Kuzmin VA, Bolton JL, Patel DJ, Broyde S, Geacintov NE.The equine estrogens equilin (EQ) and equilenin (EN) are the active components in the widely prescribed hormone replacement therapy formulation Premarin. Metabolic activation of EQ and EN generates the catechol 4-hydroxyequilenin (4-OHEN) that autoxidizes to the reactive o-quinone form in aerated aqueous solutions. The o-quinones react predominantly with C, and to a lesser extent with A and G, to form premutagenic cyclic covalent DNA adducts in vitro and in vivo. To obtain insights into the structural properties of these biologically important DNA lesions, we have synthesized site-specifically...
Machnik M, Gerlach M, Kietzmann M, Niedorf F, Thevis M, Schenk I, Guddat S, Düe M, Schänzer W.The anti-doping rules of national and international sport federations ban any use of tetrahydrogestrinone (THG) in human as well as in horse sports. Initiated by the THG doping scandals in human sports a method for the detection of 3-keto-4,9,11-triene steroids in horse blood and urine was developed. The method comprises the isolation of the analytes by a combination of solid phase and liquid-liquid extraction after hydrolysis and solvolysis of the steroid conjugates. The concentrations of THG in blood and urine samples were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS)...
Lecoq L, Vincent P, Lavoie-Lamoureux A, Lavoie JP.Glucocorticoids have potent anti-inflammatory properties and are frequently used for the treatment of domestic animal species, including horses. They induce a down-regulation of multiple inflammatory pathways through both genomic and non-genomic effects. Currently, little is known on the effects of glucocorticoids on equine peripheral blood neutrophils. Objective: Dexamethasone (DEX), a potent synthetic glucocorticoid, inhibits the functions of equine peripheral blood neutrophils through both genomic and non-genomic effects. Methods: Six healthy adult mixed breed female horses. Methods: To ass...
Anielski P.Doping control of anabolic substances is normally carried out with urine samples taken from athletes and horses. Investigation of alternative specimens, e.g. hair samples, is restricted to special cases, but can also be worthwhile, in addition to urine analysis. Moreover, hair material is preferred in cases of limited availability or complicated collection of urine samples, e.g. from horses. In this work, possible ways of interpretation of analytical results in hair samples are discussed and illustrated by practical experiences. The results demonstrate the applicability of hair analysis to det...
Yamada M, Aramaki S, Kurosawa M, Saito K, Nakazawa H.Methandienone, methandriol, and oxymetholone, which are anabolic steroids possessing 17alpha-methyl and 17beta-hydroxy groups, were developed as oral formulations for therapeutic purposes. However, they have been used in racehorses to enhance racing performance. In humans, it has been reported that structurally related anabolic steroids having the 17alpha-methyl and 17beta-hydroxy groups, including 17alpha-methyltestosterone, mestanolone, methandienone, methandriol, and oxymetholone, have metabolites in common. In this study, we found that metabolites common to those of 17alpha-methyltestoster...
Yamada M, Aramaki S, Okayasu T, Hosoe T, Kurosawa M, Kijima-Suda I, Saito K, Nakazawa H.Anabolic steroids with the 17alpha-methyl,17beta-hydroxyl group, which were developed as oral formulations for therapeutic purposes, have been abused in the field of human sports. These anabolic steroids are also used to enhance racing performance in racehorses. In humans, structurally related 17alpha-methyltestosterone (MTS) and mestanolone (MSL), which are anabolic steroids with the 17alpha-methyl,17beta-hydroxyl group, have metabolites in common. The purpose of this study was to determine metabolites common to these two steroids in horses, which may serve as readily available screening targ...
Guan F, Uboh CE, Soma LR, You Y, Liu Y, Li X.Anabolic and androgenic steroids (AASs) are synthetic substances related to the primary male sex hormone, testosterone. AASs can be abused in both human and equine sports and, thus, are banned by the International Olympic Committee and the Association of Racing Commissioners International (ARCI). Enforcement of the ban on the use of AASs in racehorses during competition requires a defensible and robust method of analysis. To address this requirement, a high-throughput ultra high-performance liquid chromatography-mass spectrometric (UHPLC-MS) method was developed for the detection, quantificati...
Lillich JD, Bertone AL, Schmall LM, Ruggles AJ, Sams RA.OBJECTIVE--To document plasma, urine, and synovial fluid disposition of 2 common intra-articularly administered steroid preparations, methylprednisolone acetate (MPA) and isoflupredone acetate (IPA). DESIGN--Descriptive investigation. SAMPLE POPULATION--100 mg of MPA or 4 mg of IPA was administered to 2 groups of 4 healthy sound radiographically normal female horses. PROCEDURE--Blood samples were collected at time 0 (before) and 2, 4, 6, 8, 10, 12, 24, 36, 48, 72, and 96 hours after administration of the designated steroid. Complete urine collection for measurement of designated steroid was ac...
Cohen ND, Carter GK.Steroid hepatopathy was diagnosed in a horse with glucorticoid-induced hyperadrenocorticism on the basis of anamnesis, serum biochemical data, and histologic findings of hepatic biopsy. Initially, clinical signs of polyuria, polydypsia, and muscular degeneration were seen. The horse developed laminitis during hospitalization.
El-Sheikh Ali H, Legacki EL, Scoggin KE, Loux SC, Dini P, Esteller-Vico A, Conley AJ, Stanley SD, Ball BA.Equine placentitis is associated with alterations in maternal peripheral steroid concentrations, which could negatively affect pregnancy outcome. This study aimed to elucidate the molecular mechanisms related to steroidogenesis and steroid-receptor signaling in the equine placenta during acute placentitis. Chorioallantois (CA) and endometrial (EN) samples were collected from mares with experimentally induced placentitis (n = 4) and un-inoculated gestationally age-matched mares (control group; n = 4). The mRNA expression of genes coding for steroidogenic enzymes (3βHSD, CYP11A1, CYP17A1, CYP19...
Toutain PL, Oukessou M, Autefage A, Alvinerie M.Using a specific high-performance liquid chromatographic technique, plasma hydrocortisone values were measured hourly in 6 horses and every 10 minutes in 4 horses over 24 hours. Both circadian and episodic variation was observed. The mean plasma hydrocortisone concentration was a maximum of 58.8 +/- 9.54 ng/ml at 9.19 +/- 0.59 hr and a minimum of 27.85 +/- 6.85 g/ml at 21.19 +/- 0.59 hr. The number of episodes of secretion was 10.0 +/- 1.41; the mean amplitude and duration of peak were 26.21 +/- 3.71 ng/ml and 105.25 +/- 21.24 min respectively.
Balssa F, Fischer M, Bonnaire Y.5(10)-Estrene-3β,17α-diol is an essential reference material for doping analysis in horse-racing laboratories. It is used to detect misuse, for doping purpose, of the pregnancy status in the mare. Its stereoselective synthesis from 17β-estradiol-3-methyl ether (prepared from estrone or 17β-estradiol) was performed in four steps: (1) Mitsunobu inversion of the 17β-alcohol; (2) Birch reduction of the aromatic ring; (3) stereoselective reduction of the 3-ketone via Noyori asymmetric transfer hydrogenation; (4) chemoenzymatic purification.
Rütten S, Schrödl W, Abraham G.Glucocorticoids are important drugs in the treatment of many inflammatory, autoimmune and allergic diseases in humans and animals. We investigated the effects of hydrocortisone and dexamethasone on TNF-α, IL-1Ra and INF-γ release in stimulated whole blood cell culture from healthy horses. Whole blood cell cultures proved to be useful for the characterization of the anti-inflammatory properties of new drugs. Diluted equine whole blood was exposed to lipopolysaccharide (LPS) and PCPwL (a cocktail consisting of phythemagglutinin E, concanavalin A, pokeweed mitogen and lipopolysaccharide) in the...
McIlwraith CW, Lattermann C.The use of intra-articular corticosteroids for traumatic arthritis and osteoarthritis (OA) is common in the horse. The beneficial and deleterious effects of the principal corticosteroids used betamethasone esters (Celestone [Soluspan], methylprednisolone acetate [Depo Medrol], and triamcinolone acetonide [TA] [Vetalog or Kenalog]) have been defined for the horse. While TA has both disease-modifying as well as symptom-modifying effects, methyl prednisolone acetate has deleterious effects on the articular cartilage. Studies in traumatically injured joints show the same rationale (suppression of ...
Boyer S, Garcia P, Popot MA, Steiner V, Lesieur M.A sensitive and specific method has been developed to detect semi-quantitatively testosterone in horse hair samples. The method involved a washing step with sodium dodecylsulfate aqueous solution. The mane and tail hair samples (100mg) were dissolved in 1 mL of sodium hydroxide for 15 min at 95 degrees C in the presence of d3-boldenone used as internal standard. The next three steps involved diethyl ether extraction and a solid phase extraction on Isolute C18 (EC) cartridges eluted with methanol. The residue was derivatized by adding 100 microL of acetonitrile and 30 microL of PFPA then incuba...
Aleman M, McCue PM, Chigerwe M, Madigan JE.Transient hypothalamic-pituitary-adrenal axis dysfunction occurs in critically ill foals with sepsis and neonatal maladjustment syndrome (NMS). Cortisol is the most commonly measured steroid. However, a complex interaction of various steroid compounds might play a role in pathophysiology of this disorder. Objective: To identify steroid compounds present at high concentrations at birth that rapidly and steadily decrease within the first 7 days of life in healthy foals and that might be supportive diagnosis of NMS and other neonatal disorders. Methods: Ten healthy neonatal Quarter Horse foals ...
Thomas PG, Ignotz GG, Ball BA, Miller PG, Brinsko SP, Currie B.Oviduct epithelial cells (OEC) increasingly are used to support embryonic development and to study gamete interactions with the female reproductive tract in vitro. This series of experiments was designed to characterize monolayers derived from oviduct epithelium. Epithelial cells harvested from the isthmus and ampulla of the oviducts of five estrous mares were cultured with or without the basal lamina extract, Matrigel. Within each group OEC were cultured in the presence of either estradiol-17 beta or a carrier control. All groups were subcultured three times. Epithelial cell morphology and fu...
Zhang N, Ding S, Kolbanovskiy A, Shastry A, Kuzmin VA, Bolton JL, Patel DJ, Broyde S, Geacintov NE.The equine estrogens equilin (EQ) and equilenin (EN) are the active components in the widely prescribed hormone replacement therapy formulation Premarin. Metabolic activation of EQ and EN generates the catechol 4-hydroxyequilenin (4-OHEN) that autoxidizes to the reactive o-quinone form in aerated aqueous solutions. The o-quinones react predominantly with C, and to a lesser extent with A and G, to form premutagenic cyclic covalent DNA adducts in vitro and in vivo. To obtain insights into the structural properties of these biologically important DNA lesions, we have synthesized site-specifically...
You Y, Uboh CE, Soma LR, Guan F, Li X, Liu Y, Rudy JA, Chen J, Tsang D.The potential for using testosterone and nandrolone esters in racehorses to boost the biological concentrations of these steroids and enhance athletic performance is very compelling and should be seriously considered in formulating regulatory policies for doping control. In order to regulate the use of these esters in racehorses, a sensitive and validated method is needed. In this paper, we report such a method for simultaneous separation, screening, quantification and confirmation of 16 testosterone and nandrolone esters in equine plasma by ultra high performance liquid chromatography-tandem ...
Aguiar FL, Lunardi FO, Lima LF, Rocha RM, Bruno JB, Magalhães-Padilha DM, Cibin FW, Nunes-Pinheiro DC, Gastal MO, Rodrigues AP, Apgar GA, Gastal EL....This study investigated the effect of adding different concentrations of bovine recombinant follicle-stimulating hormone on the IVC of equine preantral follicles enclosed in ovarian tissue fragments. Randomized ovarian fragments were fixed immediately (fresh noncultured control) or cultured for 1 or 7 days in α-MEM(+) supplemented with 0, 10, 50, and 100 ng/mL FSH and subsequently analyzed by classical histology. Culture media collected on Day 1 or Day 7 and were analyzed for steroids (estradiol and progesterone) and reactive oxygen species (ROS). After Day 1 and Day 7 of culture, 50-ng/mL FS...
Goff AK, Leduc S, Poitras P, Vaillancourt D.The objective of this study was to determine if changes in steroid synthesis occurred in the horse blastocyst about the time of maternal recognition of pregnancy. Embryos collected between days 7.5 and 14.5 were incubated for 8 hr in vitro in HAM's F10 containing radiolabelled pregnenolone. The steroid metabolites in the incubation medium were separated by reverse phase HPLC and the major peaks expressed as a percentage of total metabolites. It was found that there were no major changes in the profile of metabolites throughout the period of study, although there was increased conversion as the...
Mainguy-Seers S, Boivin R, Pourali Dogaheh S, Beaudry F, Hélie P, Bonilla AG, Martin JG, Lavoie JP.Steroid resistance in asthma has been associated with neutrophilic inflammation and severe manifestations of the disease. Macrolide add-on therapy can improve the quality of life and the exacerbation rate in refractory cases, possibly with greater effectiveness in neutrophilic phenotypes. The mechanisms leading to these beneficial effects are incompletely understood and whether macrolides potentiate the modulation of bronchial remodeling induced by inhaled corticosteroids (ICS) is unknown. The objective of this study was to determine if adding azithromycin to ICS leads to further improvement o...
McDowell KJ, Adams MH, Franklin KM, Baker CB.A cDNA library was constructed from poly(A) RNA obtained from Day 14 nonbred equine endometrium. A cDNA probe for porcine retinol-binding protein (RBP) was used to screen the library, and a complete cDNA sequence (1133 bp, excluding the poly(A) tail) was obtained. Endometrial biopsies were obtained from cycling, nonbred mares at Days 0, 1, 4, 8, 10, 11, 13, and 15 and from pregnant mares at Days 11, 13, 15, and 17 after ovulation (n = 2 mares each day). Endometrial biopsies were also taken from 18 noncycling anestrous mares after the following treatments: C (vehicle control for 1 day, n = 3), ...
Lees P, Higgins AJ, Sedgwick AD, May SA.The development of reproducible models of acute inflammation in which inflammatory heat is easily quantified and from which inflammatory exudate is readily harvested has facilitated studies in the horse of the actions of steroids and non-steroidal anti-inflammatory drugs (NSAIDS). Blockade of the synthesis of eicosanoids and suppression of inflammatory heat by clinical dose rates of NSAIDS suggests a causal link between the two events and provides further evidence for a role of these compounds in acute equine inflammation. The tendency for enolic and carboxylic acids NSAIDS to accumulate in in...
Raeside JI, Renaud RL.Isolation of 3 beta-hydroxy-5,7-androstadien-17-one, as a major component of steroids extracted from vein blood of the fetal gonads of the horse, supports the proposed role for the compound as a precursor for equilin formation in the placenta of the mare. The 5,7-diene was extracted from blood collected from gonadal veins of fetal ovaries and testes in situ, and from a fetal testis connected to an artery in the neck region of the mare. Perfusion of fetal gonads in the laboratory was carried out to allow longer periods of collection. In addition, isolated cell preparations from a fetal testis w...
Tou K, Cawley A, Bowen C, Sornalingam K, Fu S.The conventional detection of exogenous drugs in equine doping samples has been used for confirmation and subsequent prosecution of participants responsible. In recent years, alternative methods using indirect detection have been investigated due to the expanding number of pharmaceutical agents available with the potential of misuse. The monitoring of endogenous biomarkers such as hydrocortisone (HC) has been studied in equine urine with an international threshold of 1 μg/ml established; however, there is no current threshold for equine plasma. The aim of this research was to investigate pl...
Ryu SH, Kim BS, Lee CW, Yoon J, Lee YL.A 3-year-old Thoroughbred filly was referred to the Equine Hospital, Korea Racing Association for evaluation of hematuria, inappetite, weight loss and depression. From 25 days prior to admission, the horse was treated for right carpal lameness with 20 mg intramuscular administration of triamcinolone acetonide per day for consecutive 10 days by a local veterinarian. Clinical and laboratory findings included vaginal hyperemia, flare in bladder wall, neutrophilia, lymphopenia, polyuria, polydipsia and laminitis in the end. High activities of aspartate transaminase and gamma glutamyltransferase an...
Anielski P, Thieme D, Schlupp A, Grosse J, Ellendorff F, Mueller RK.Growing interest among several horse-breeder associations has initiated the development of a screening procedure to test for anabolic agents in hair, which has the advantage over blood and urine specimens of allowing long-term detection. An analytical method was established to monitor in tails or manes several anabolic substances available as veterinary medicines or as so-called nutritional supplements (clenbuterol, different esters or prohormones of nandrolone and testosterone). The analytical procedure to detect steroids in hair samples consists of the following steps: decontamination of the...
Bridges TS, Davidson TR, Chamberlain CS, Geisert RD, Spicer LJ.The objective of the present study was to evaluate changes in equine follicular fluid insulin-like growth factor binding protein (IGFBP) proteolytic activity as well as steroid, IGF, and IGFBP concentrations during follicular development in the mare. Mares (n = 14) were classified as either in the follicular phase (n = 8) or luteal phase (n = 6). Follicles (n = 92) were categorized as small (6 to 15 mm; n = 54), medium (16 to 25 mm; n = 23), or large (> 25 mm; n = 15), and follicular fluid was collected. Estradiol and androstenedione levels in follicular fluid were greater (P < 0.05), an...
Lemazurier E, Sourdaine P, Nativelle C, Plainfossé B, Séralini G.Adult stallion secretes very high estrogen levels in its testicular vein and semen, and the responsible enzyme cytochrome P450 aromatase (P450 arom) is known to be present mainly in Leydig cells. We studied in further details the distribution of equine aromatase in various adult tissues including the brain (hypothalamic area), liver, kidney, small intestine, muscle, bulbourethral gland and testes. The aromatase mRNA was essentially detected by RT-PCR in testis (169+/-14 amol of aromatase mRNA per microg of total RNA) and was barely detectable in brain, or below 0.1 amol/microg RNA in other tis...
Perkins GA, Miller WH, Divers TJ, Clark CK, Belgrave RL, Sellon DC.This report describes transient ulcerative dermatitis, severe thrombocytopenia, and mild neutropenia in 6 foals from 4 mares from geographically diverse regions of the United States. The foals presented at <4 days of age with oral and lingual ulcers, and crusting and erythema around the eyes, muzzle, and perineal, inguinal, axillary, trunk, and neck regions. There was a severe thrombocytopenia (0-30,000 platelets/microL), leukopenia (1900-3200 white blood cells/microL), and mild neutropenia (500-1800 neutrophils/microL). Four of the 6 foals had petechiae and ecchymotic hemorrhages and 3 had bl...
Gray BP, Biddle S, Pearce CM, Hillyer L.Fluticasone propionate (FP) is an anti-inflammatory agent with topical and inhaled applications commonly used in the treatment of asthma in steroid-dependent individuals. The drug is used in racehorses to treat Inflammatory Airway Disease; this work was performed in order to advise on its use and detect potential misuse close to racing. Methods were developed for the extraction and analysis of FP from horse plasma and a carboxylic acid metabolite (FP-17βCOOH) from horse urine. The methods utilize ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in ...
Kaabia Z, Dervilly-Pinel G, Hanganu F, Cesbron N, Bichon E, Popot MA, Bonnaire Y, Le Bizec B.During last decades, the use of natural steroids in racing and food producing animals for doping purposes has been flourishing. The endogenous or exogenous origin of these naturally occurring steroids has since remained a challenge for the different anti-doping laboratories. The administration of these substances to animals is usually made through an intra-muscular pathway with the steroid under its ester form for a higher bioavailability and a longer lasting effect. Detecting these steroid esters would provide an unequivocal proof of an exogenous administration of the considered naturally occ...
Trahan RA, Byron CR, Dahlgren LA, Pleasant RS, Werre SR.OBJECTIVE To compare the effects of 3 equimolar concentrations of methylprednisolone acetate (MPA), triamcinolone acetonide (TA), and isoflupredone acetate (IPA) on equine articular tissue cocultures in an inflammatory environment. SAMPLE Synovial and osteochondral explants from the femoropatellar joints of 6 equine cadavers (age, 2 to 11 years) without evidence of musculoskeletal disease. PROCEDURES From each cadaver, synovial and osteochondral explants were harvested from 1 femoropatellar joint to create cocultures. Cocultures were incubated for 96 hours with (positive control) or without (n...
Fugazzola M, Barton AK, Niedorf F, Kietzmann M, Ohnesorge B.Glucocorticoids have been proven to be effective in the therapy of recurrent airway obstruction (RAO) in horses via systemic as well as local (inhalative) administration. Elective analysis of the effects of this drug on bronchoconstriction in viable lung tissue offers an insight into the mechanism of action of the inflammatory cascade occurring during RAO which is still unclear. The mechanism of action of steroids in treatment of RAO is thought to be induced through classical genomic pathways. We aimed at electively studying the effects of the glucocorticoid beclomethasone dipropionate on equi...
