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.
Tait AD, Santikarn S, Allen WR.The 5,7-dienes, 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one were extracted from fetal horse gonads and purified by solvent partition, thin-layer chromatography and high performance liquid chromatography. The isolated steroids were identified by comparison with the synthetic steroids using ultraviolet and mass spectroscopy and by gas chromatography-mass spectroscopy. The identification of these compounds as endogenous steroids, together with the data on their biosynthesis reported previously, support the proposal that in the fetal horse gonad there is a 5,7-d...
Blanchard TL, Elmore RG, Youngquist RS, Loch WE, Hardin DK, Bierschwal CJ, Ganjam VK, Balke JM, Ellersieck MR, Dawson LJ, Miner WS.Fifty mature pony stallions were randomly assigned to one of five treatment groups: Group 1- controls (no treatment), Group 2 - 0.55 mg/kg stanozolol weekly for 13 treatments, Group 3 - 1.1 mg/kg stanozolol every 3 weeks for 5 treatments, Group 4 - 1.1 mg/kg boldenone undecylenate every 3 weeks for 5 treatments, and Group 5 - 0.55 mg/kg boldenone undecylenate weekly for 13 treatments. Scrotal widths (SW), combined testis weights (CTW), and daily sperm productions (DSP) were not different between Groups 1 and 2. Ponies in Group 5 had smaller SW (P<0.01), smaller CTW and decreased DSP compare...
Weiser G, Kohn C, Vachon A.Immune-mediated hemolytic anemia was diagnosed in two horses on the basis of regenerative anemia, increased erythrocyte fragility in hypotonic saline, autoagglutination, and a positive direct antiglobulin (Coomb's) test. During steroid therapy partial resolution of the anemia was indicated by rising packed cell volume, macrocytosis, and bone marrow erythroid hyperplasia. Using erythrocyte volume distribution histograms (erythrograms), the regenerative response was characterized by analysis of macrocytic and normocytic erythrocyte subpopulations. In both horses, a gradual net increase of about ...
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.
Raeside JI, Gofton N, Liptrap RM, Milne FJ.Direct connection of the artery of a fetal ovary to the carotid artery of the mare allowed collection of a large volume of blood over a 30-min period. Extraction of steroids and their fractionation was followed by separation of the steroids by alumina adsorption chromatography, and Sephadex LH-20 and Celite partition chromatography. Further resolution of the material by HPLC led to the identification of dehydroepiandrosterone (DHA) by nuclear magnetic resonance and mass spectrometry. Other compounds were isolated, which remain to be identified fully, but in the 8th month of pregnancy the princ...
Setchell BP, Cox JE.In 3 testes of 2 adult Pony stallions under halothane anaesthesia, catheters were inserted into a vein and a lymphatic vessel in the spermatic cord and into a vein on the surface of the testis. Lymph and venous blood were collected from the catheters in the cord and p-aminohippurate (2% w/v, 0 . 1 ml/min) was infused into the vein on the testis to determine blood flow by dilution. After 1 h, 6000 i.u. hCG was injected i.v. and collections continued for 45 min. The testes weighed 126-176 g. Lymph flow was 20-150 microliter/min before hCG and 100-270 microliter/min after hCG; the range of blood ...
Houghton E, Dumasia MC, Wellby JK.Negative ion chemical ionization mass spectra of some corticosteroids have been obtained by direct syringe introduction on to the Finnigan moving belt high-performance liquid chromatography-mass spectrometer interface. Proprietary preparations based upon dexamethasone, betamethasone and prednisolone were administered to horses at therapeutic dose level. Urine samples were extracted, the extracts purified by Sephadex LH-20 chromatography and the presence of the parent steroids in the eluates was confirmed by combined high-performance liquid chromatography negative ion chemical ionization mass s...
Bhavnani BR, Woolever CA.[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...
Eiler H, Goble D, Oliver J.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...
Garcia MC, Freedman LJ, Ginther OJ.A working hypothesis for the regulation of LH secretion in the mare is postulated which involves the following two components: (1) a primary central nervous system (CNS)-pituitary component which is responsible for a basal circannual LH rhythm, entrained to an environmental 'Zeitgeber' (most probably photoperiod) and independent of ovarian influences, and (2) a secondary ovarian (steroidal) component which modifies the primary rhythm during the ovulatory season. This hypothesis does not seem to apply in its entirety to FSH secretion; the CNS-pituitary component is demonstrable within the first...
Eyre P, Elmes PJ, Strickland S.Spirally cut digital arteries and veins were mounted isotonically in organ baths containing oxygenated Krebs' Q-Henseleit solution. Twelve arterial and 12 venous preparations all contracted dose dependently when epinephrine, norepinephrine, serotonin, or histamine were added to the bathing fluid. Addition of hydrocortisone or betamethasone alone did not cause contractions in any of the tissues tested. However, when hydrocortisone or betamethasone was added to vessel strips that were partially contracted (40% to 60% maximal) by epinephrine, norepinephrine, or serotonin, each vessel strip invari...
Merchant-Larios H.The establishment and sexual differentiation of the gonads of horse embryos were studied using high-resolution techniques. The most dramatic observation is the early cytodifferentiation of the somatic cells into steroidogenic cells which takes place before sexual differentiation of the gonads. A unique morphogenetic pattern is established during this process: the seminiferous cords of the testis are completely segregated from the steroidogenic tissue by a basal lamina, while in the medulla of the ovary, steroidogenic cells differentiate inside the epithelial cords which contain germ cells. Thi...
Pashen RL, Allen WR.The effects of fetal gonadectomy on steroid production and the maintenance of pregnancy in the mare were studied. Removal of the fetal gonads resulted in an immediate fall in maternal plasma concentrations of conjugated and unconjugated oestrogens whereas progestagen levels remained unchanged. Hormone profiles in mares carrying sham-operated fetuses remained similar to those in unoperated control mares. Plasma levels of 13,14-dihydro-15-oxo-PGF-2 alpha (PGFM) were much lower, and uterine contractions weaker, during labour in mares carrying gonadectomized foals than in control mares. Pregnancy ...
Bhavnani BR, Woolever CA.A mixture of [4,8,12-14C]farnesyl pyrophosphate and [3H]dehydroepiandrosterone was injected into a horse fetus im during laparotomy, after which maternal urine was collected for 6 days. Steroid conjugates in the urine were extracted with Amberlite XAD-2 resin, hydrolyzed, and separated into phenolic and neutral fractions. Estrone, 17 alpha-estradiol, equilin [3-hydroxy-1,3,5(10),7-estratetraen-17-one], and 17 alpha-dihydroequilin [1,3,4(10),7-estratetraene-3,17 alpha-diol] were isolated from the phenolic fraction and their radiochemical purities were established. Only estrone and 17 alpha-estr...
Magnuson NS, McGuire TC, Banks KL, Perryman LE.The in vitro and in vivo effects of corticosteroids on peripheral blood lymphocytes (PBL) from ponies were studied. Prednisolone inhibited lymphocyte stimulation by phytohemagglutin (PHA) in a dose-dependent manner, without inducing lysis even at large doses. The PBL from horses heterozygous for the combined immunodeficiency trait responded to corticosteroid treatment the same as did PBL from normal ponies. Removal of the corticosteroid after incubation with PBL from normal ponies partially restored responsiveness of these cells to PHA. Chronic in vivo treatment of ponies with corticosteroids ...
Kenney RM.Normal histologic changes that occurred in concert with the ovarian cycle were evaluated. When combined with behavioral and physical findings, this evaluation enabled determination when there was synchrony between ovarian steroids (estrogen and progesterone) and their target tissues of endometrium. A system for classification as well as definitions of patterns types and degrees of severity of inflammatory and fibrotic changes was developed to facilitate a uniform system for description and communication. An attempt was made to relate the pathologic changes to their effect on fertility when fer...
Chapman DI, Whiteside J.A radioimmunoassay method has been developed that enables the administration of therapeutic doses of synthetic corticosteroids to be detected in horse urine. Fourteen proprietary preparations of these steroids have been given by intramuscular injection to ponies and thoroughbreds. The administration of some preperations could still be detected six days after a single intramuscular injection of a therapeutic dose. The route of injection of dexamethasone-21-sodium phosphate, whether intramuscular, intravenous or intra-articular, did not appear to alter the length of time over which the steroid o...
Samuel CA, Allen WR, Steven DH.In early pregnancy the equine placenta consists of a simple apposition of fetal and maternal epithelia, but it becomes more complex with the formation of microcotyledons between 75 and 100 days of gestation. Although the placental barrier maintains an epitheliochorial arrangement throughout the course of pregnancy, a thinning of the maternal epithelium and a progressive indentation of the chorionic epithelium by fetal capillaries shortens the length of the diffusion pathway and reduces the amount of placental tissue between fetal and maternal bloodstreams. These structural modifications may re...
Hillensjö T, Bauminger S, Ahrén K.Preovulatory follicles were explanted on the day before ovulation from immature rats given a single injection of Pregnant Mare's Serum gonadotropin (PMS) 2 days earlier. The follicles were incubated for 4 h in modified Krebs bicarbonate buffer containing glucose and albumin in absence or presence of ovine luteinizing hormone (NIH-LH-S18; 0.1-10 mug/ml). The accumulation of progresterone, androstenedione and 17beta-estradiol in the medium was determined by radioimmunoassay. As in indicator of LH exposure the meiotic stage of the follicle-enclosed oocyte was determined at recovery by interferenc...
Hay MF, Allen WR.Gonadal tissue obtained at about 50-day intervals from Days 60 to 300 of gestation was examined histologically, histochemically and in the electron microscope. The marked enlargement of the gonads (ovaries or testes) reached a peak around Day 250 and was caused by hypertrophy and hypoplasia of interstitial cells. These cells had all the ultrastructural characteristics of a steroid-secreting cell but delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) was not detected at any stage of their development. There was no significant change in the ultrastructure of the interstitial cells between Day...
Yamauchi S.The luminal and cut surface of endometrial cups were examined by scanning electron microscopy. The distribution of PAS-positive and lipid materials in cup tissue was studied and most of the lipid material was localized in the large polyhedral cup cells. The lipid droplets gave positive reactions for DNPH in the cholesterol test of Schultz. They also exhibited autofluorescence and were therefore considered to be steroidal in nature. The significance of this possibility, particularly with regard to maintenance of early pregnancy in the mare, is discussed.
Bhavnani BR, Martin LJ, Baker RD.A mixture of 1-14C-isopentenylpyrophosphate and 3H-dehydroisoandrosterone was injected into a horse fetus intramuscularly during laparotomy, after which maternal urine was collected for 4 days. Steroid conjugates in the urine were extracted with Amberlite XAD-2 resin, hydrolysed and separated into phenolic and neutral fractions. From the phenolic fraction estrone, 17alpha-estradiol, equilin and equilenin were isolated. Only estrone and 17alpha-estradiol contained both 3H and 14C, while the ring B unsaturated estrogens contained only 14C. From the neutral fraction 14C-labeled 3beta-hydroxy-5alp...
Apukhovska LI, Vendt VP, Ivashkevych SP.Sterols of the whole erythrocytes, hemoglobin, membranes and their protein fractions were studied. Erythrocytes and their components were established to contain, besides cholesterol, other substances of the sterol nature. Cholesterol, 7-dehydrocholesterol and other substances of the cholesterol series are practically completely linked with the lipoproteid fractions of the erythrocyte membrane whereas all sterols found in the native erythrocytes in negligible amounts are bound with hemoglobin.
Allen RG.The presently used procedures for the colorimetric determination of conjugated estrogens (equine) have been modified for the assay of tablets, capsules, liquids, and creams of low declaration per dosage unit. Modifications in sample chromatographic column preparation and elution have provided a more efficient extraction of the steroids.
Knickelbein KE, Luethy D, Thomasy SM, Reilly C, Strom AR, Lassaline ME.(a) To evaluate the epidemiology of equine eosinophilic keratoconjunctivitis (EK) in the western United States, (b) to ascertain the efficacy of keratectomy and diamond burr debridement vs medical management alone, (c) to determine the efficacy of various medical therapies, and (d) to further characterize the histopathologic findings of the disease in horses. Methods: Twenty-nine horses (47 eyes) diagnosed with EK from 1993 to 2017. Methods: Retrospective medical record review; owner questionnaire. Results: Average age of presentation was 11 ± 4 years. Warmbloods were significantly overrep...
Geor R, Hope E, Lauper L, Piela S, Klassen J, King V, Murphy M.The effects of dexamethasone (0.2 mg/kg of body weight; IV, IM, and PO) and methylprednisolone acetate (120 mg given intra-articularly) on serum osteocalcin and cortisol concentrations were studied in 6 horses. Serum osteocalcin and cortisol concentrations were serially monitored after each treatment. A significant (P < 0.05) decrease in serum osteocalcin and cortisol concentrations was observed from 12 to 24 and 2 to 48 hours, respectively, after IV and IM administrations of dexamethasone. Serum osteocalcin and cortisol concentrations were significantly decreased from 6 to 48 and 3 to 72 h...
Smith SJ, Cox JE, Houghton E, Dumasia MC, Moss MS.Deuterium, 14C- and 3H-labelled steroid substrates were incubated with minced testicular tissue from stallions of different ages. After extraction and separation of the neutral and phenolic fractions the metabolites were identified by gas chromatography-mass spectrometry. The presence of the expected C19 neutral and C18 phenolic steroids was confirmed. An isomer of 5(10)-oestrene-3,17-diol was also identified.
Dumasia MC, Houghton E.The in vivo biotransformation of (1,2(n)-3H)1-dehydrotestosterone was studied in three equine male castrates and a number of neutral metabolites were identified in the urinary unconjugated and glucuronic acid conjugate fractions by gas chromatography/mass spectrometry. The metabolites were extracted from aliquots of the 0-24 h urine samples by Amberlite XAD-2 and separated into combined unconjugated plus glucuronic acid conjugated and sulphoconjugated fractions by Sephadex LH-20 column chromatography. After enzymatic hydrolysis of the glucuronides, the crude neutral unconjugated steroids plus ...
Raeside JI, Gofton N, Liptrap RM, Milne FJ.Direct connection of the artery of a fetal ovary to the carotid artery of the mare allowed collection of a large volume of blood over a 30-min period. Extraction of steroids and their fractionation was followed by separation of the steroids by alumina adsorption chromatography, and Sephadex LH-20 and Celite partition chromatography. Further resolution of the material by HPLC led to the identification of dehydroepiandrosterone (DHA) by nuclear magnetic resonance and mass spectrometry. Other compounds were isolated, which remain to be identified fully, but in the 8th month of pregnancy the princ...
Bhavnani BR, Martin LJ, Baker RD.A mixture of 1-14C-isopentenylpyrophosphate and 3H-dehydroisoandrosterone was injected into a horse fetus intramuscularly during laparotomy, after which maternal urine was collected for 4 days. Steroid conjugates in the urine were extracted with Amberlite XAD-2 resin, hydrolysed and separated into phenolic and neutral fractions. From the phenolic fraction estrone, 17alpha-estradiol, equilin and equilenin were isolated. Only estrone and 17alpha-estradiol contained both 3H and 14C, while the ring B unsaturated estrogens contained only 14C. From the neutral fraction 14C-labeled 3beta-hydroxy-5alp...
Agrawal K, Ebel JG, Bischoff K.Most antidoping method development in the equine industry has been for plasma and urine, though there has been recent interest in the analysis of synovial fluid for evidence of doping by intra-articular corticosteroid injection. Published methods for corticosteroid analysis in synovial fluid are primarily singleplex methods, do not screen for all corticosteroids of interest and are not adequately sensitive. The purpose of this study is to develop a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) screening method for the detection of four of the most common intra-a...
Chapman DI, Whiteside J.A radioimmunoassay method has been developed that enables the administration of therapeutic doses of synthetic corticosteroids to be detected in horse urine. Fourteen proprietary preparations of these steroids have been given by intramuscular injection to ponies and thoroughbreds. The administration of some preperations could still be detected six days after a single intramuscular injection of a therapeutic dose. The route of injection of dexamethasone-21-sodium phosphate, whether intramuscular, intravenous or intra-articular, did not appear to alter the length of time over which the steroid o...
Aguilera R, Becchi M, Mateus L, Popot MA, Bonnaire Y, Casabianca H, Hatton CK.A gas chromatography-combustion-isotope ratio mass spectrometry method for confirmation of hydrocortisone abuse in horseracing and equine sports is proposed. Urinary hydrocortisone was converted to a bismethylenedioxy derivative which presents good gas chromatographic properties and brings an extra carbon contribution of only two carbon atoms. Synthetic hydrocortisone has a different 13C abundance from that of natural urinary horse hydrocortisone and the difference is significant, therefore exogenous and endogenous hydrocortisone can be distinguished.
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.
Allen RG.The presently used procedures for the colorimetric determination of conjugated estrogens (equine) have been modified for the assay of tablets, capsules, liquids, and creams of low declaration per dosage unit. Modifications in sample chromatographic column preparation and elution have provided a more efficient extraction of the steroids.
Dumasia MC, Houghton E.The research investigates the biosynthesis of a particular isomer called 5(10)-estrene-3 alpha, 17 beta-diol in stallion testes and how it affects the formation of 19-nor steroids and oestrogens. Summary of […]
Kong FKW, Wong ASY, Wan TSM, Ho ENM.Hydrocortisone acetate, a synthetic acetate ester of hydrocortisone, was detected in horse blood samples collected from Thoroughbreds. Hydrocortisone acetate is generally considered an indicator for exogenous administration in horses. As hydrocortisone acetate has been previously reported to be endogenous in selected mammals, a proof-of-concept study was performed to evaluate the possible endogenous nature of hydrocortisone acetate in horses by in vitro incubation experiments using homogenized horse brain tissue.
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...
Atai T, Ozmaie S, Anoushepour A.This research was performed to compare the effects of prednisolone and fluorometholone on intraocular pressure (IOP) and Schirmer tear test (STT) in the normal equine eye. Sixteen normal mares aged between 6 and 10 years were used for this study. Horses were randomly assigned to two groups. Eight horses in the first group received 0.2 mL of topical 1% prednisolone in one eye and the contralateral eye was used as control (0.2 mL of saline was instilled). The second group received 0.2 mL of 0.1% fluorometholone in a randomly selected eye and the contralateral eye served as control and received 0...
Capolongo F, Gallina G, Fidani M, Baia F, Montesissa C.This study investigated whether a single intra-articular administration (IA) of dexamethasone (DEX) in horses at therapeutic dosage could exert a systemic effect by influencing the hypothalamic-pituitary-adrenal axis activity as a consequence of (limited) absorption and systemic distribution. The results indicated that DEX was detectable in urine collected 12-48 h after IA administration and that injection was accompanied by a reduced urine excretion of cortisol, 6β-hydroxycortisol (6βOHF) and two other metabolites of cortisol lasting up to 48 h post-DEX administration. The systemic effect...
Hagedorn HW, Schulz R.Statistical analysis of normally occurring cortisol levels in serum and urine of horses served to recommend thresholds for this corticosteroid in these body fluids, as application of exogenous cortisol as well as ACTH may elevate the cortisol concentrations above the proposed threshold. The present study contributes to the general issue of how to establish thresholds for trotting horses upon sportive examination. 100 randomly selected post competition serum and urine samples, respectively, were submitted to cortisol analysis by means of HPLC. Concentrations of the endogenous corticosteroid in ...
Gu X, Meleka-Boules M, Chen CL.A capillary electrophoresis technique was developed for the separation of synthetic glucocorticoids and the determination of dexamethasone and flumethasone in horse urine. Pretreatment of the sample using a dexamethasone affinity column resulted in low background that enabled the authors to detect levels as low as 1.1 ng/mL and 2.7 ng/mL for dexamethasone and flumethasone in horse urine, respectively. The developed method was used to detect dexamethasone in horse urine samples after the injection of a therapeutic dose of dexamethasone for up to 12 hr postinjection. The optimum conditions for c...
Wong JKY, Leung DKK, Curl P, Schiff PJ, Lam KKH, Wan TSM.The detection of boldenone, nandrolone, 5(10)-estrene-3β,17α-diol, and 4-estrene-3,17-dione in a urine sample collected from a gelding having been treated with testosterone (500 mg 'Testosterone Suspension 100', single dose, injected intramuscularly) in 2009 led the authors' laboratory to suspect that these 'testicular' steroids could be minor metabolites of testosterone in geldings. Administration trials on six castrated horses with Testosterone Suspension 100 confirmed that low levels of boldenone, nandrolone, 5(10)-estrene-3β,17α-diol, and 4-estrene-3,17-dione could indeed be detected ...
Skrabalak DS, Cuddy KK, Henion JD.Micro-liquid chromatography-mass spectrometry (micro-LC-MS) was utilized to quantitatively determine betamethasone and its major unconjugated metabolite, 6 beta-hydroxybetamethasone, in equine plasma and urine. The advantage of micro-LC-MS over conventional gas chromatography-mass spectrometry in corticosteroid determination is illustrated and the reliable, steadfast nature of micro-LC-MS is demonstrated through example.
Edlund PO, Bowers L, Henion J.Monitoring steroid use requires an understanding of the metabolism in the species in question and development of sensitive methods for screening of the steroid or its metabolites in urine. Qualitative information for confirmation of methandrostenolone and identification of its metabolites was primarily obtained by coupled-column high-performance liquid chromatography-tandem mass spectrometry. The steroids and a sulphuric acid conjugate were isolated and identified by their daughter ion mass spectra in the urine of both man and the horse following administration of methandrostenolone. Spontaneo...
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...
Koskinen E, Andersson M, Katila T.The effect of anabolic steroid on testicular growth was investigated in 3 experiments. In experiment I, 500 mg of the anabolic steroid was given to 4 colts and 100 mg to another 4 colts, every 3rd week, starting at age 16 months and ending at age 24 months. Six colts served as controls. Both treatments decreased total scrotal width (TSW) within 6 weeks. Seasonal testicular growth during spring partly overcame the effect of steroid treatment. Cessation of anabolic steroid treatment was followed by testicular growth at the same time as TSW in untreated colts was decreasing by virtue of the effec...
Houghton E, Copsey J, Dumasia MC, Haywood PE, Moss MS, Teale P.As part of a continuing research program associated with the detection of anabolic steroid residues in horse urine, normal samples from entire male horses have now been investigated. Isomers of three C-18 neutral steroids; 4-estren-17-ol-3-one (1), estrane-3,17-diol (2) and an unsaturated estranediol having a possible structure (3), have been identified in urine samples from two male horses aged 8 and 14 years. Of these three steroids, compound (2) was not detected in the urine of a 2.5 yr old entire male nor in the majority of post-race urine samples from entire male horses average age 3.8 yr...
Singh AK, Gordon B, Hewetson D, Granley K, Ashraf M, Mishra U, Dombrovskis D.Gas chromatography with chemical ionization mass spectrometry and selected-ion monitoring provided a sensitive method for the screening and confirmation of steroids in horse urine and plasma. Chemical ionization mass spectrometry was more sensitive than the electron impact ionization mass spectrometry for most of the steroids except for testosterone, prednisone-metabolite-2 and prednisolone-metabolite-2. The chromatographic conditions used in this study provided clean separation of different natural and synthetic steroids. Approximately 75-85% of the steroids added to plasma and approximately ...
Marshall DE, Mortishire-Smith RJ, Houghton E, Gower DB.Oestradiene-3,17-diol and oestratriene-3,17-diol (or the diol of Heard's ketone (3-hydroxy-5(10),6,8-oestratriene-17-one) have been extracted on a large scale from pooled urines and allantoic fluid obtained from pregnant mares. Initial purification was achieved using column chromatography, and further purification by high performance liquid chromatography or silver nitrate (argentation) thin layer chromatography. The steroids were characterised using gas chromatography-mass spectrometry. Positions of the double bonds in ring B of oestradienediol were deduced on the basis of results of ultravio...
