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Topic:Quantitative PCR

Quantitative PCR (qPCR) is a molecular technique utilized to amplify and quantify DNA sequences in a sample, providing insights into gene expression levels and pathogen load in horses. This method is widely used in equine research for its sensitivity and precision in detecting genetic material, making it valuable for studying infectious diseases, genetic disorders, and other health conditions in horses. qPCR can quantify the expression of specific genes, allowing researchers to assess the impact of various factors on equine health and physiology. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, methodologies, and implications of quantitative PCR in equine science.
Expression pattern of germ cell markers in cryptorchid stallion testes.
Reproduction in domestic animals = Zuchthygiene    April 13, 2024   Volume 59, Issue 4 e14561 doi: 10.1111/rda.14561
Shakeel M, Choi Y, Yoon M.Cryptorchidism affects spermatogenesis and testis development, often resulting in stallion subfertility/infertility. This study aims to identify the specific germ cells impacted by cryptorchism in stallions. In a previous study, we found that PGP9.5 and VASA are molecular markers expressed in different germ cells within stallions. Herein, we assessed the heat stress-induced response of spermatogonial stem cells (SSCs) in the seminiferous tubules (ST) of cryptorchid stallion testes (CST) and normal stallion testes (NST). This goal was accomplished by comparing PGP9.5 and VASA expression pattern...
Low levels of microRNA-21 in neutrophil-derived exosomes may contribute to airway smooth muscle hyperproliferation in horses with severe asthma.
American journal of veterinary research    February 12, 2024   1-8 doi: 10.2460/ajvr.23.11.0267
Vargas A, Mainguy-Seers S, Boivin R, Lavoie JP.Neutrophilic inflammation is associated with the degree of airway obstruction in severe equine asthma (SEA), but the contribution of these leukocytes to bronchial remodeling remains ill defined. Neutrophils could cause structural alterations of the airways by the release of exosomes, a type of cell-derived nanoparticles that can modify the biology of local and distant cells. Neutrophil-derived exosomes have been shown to increase airway smooth muscle (ASM) cell proliferation in humans and horses. Therefore, this study aimed to identify neutrophil exosomal microRNAs (miRs) implicated in the reg...
Development and evaluation of a real-time quantitative PCR for the detection of equine infectious anemia virus.
Microbiology spectrum    October 9, 2023   e0259923 doi: 10.1128/spectrum.02599-23
Li S, Guo K, Wang X, Lin Y, Wang J, Wang Y, Du C, Hu Z, Wang X.Equine infectious anemia (EIA) has a worldwide distribution and causes severe economic losses to the equine industry. The EIA virus (EIAV) genome sequences from different countries are highly diverse, which poses a great challenge for pathogen identification with PCR. Phylogenetic analysis showed that although gag is the most conserved structural gene, it still has great genome variability. Currently, most existing PCR methods are designed based on the gag gene sequence and therefore do not cover all the viral strains, especially Asian EIAV strains. In this study, we developed a tat-gag-based ...
Identification of Potential miRNA Biomarkers to Detect Hydrocortisone Administration in Horses.
International journal of molecular sciences    September 25, 2023   Volume 24, Issue 19 14515 doi: 10.3390/ijms241914515
Kikuchi M, Ishige T, Minamijima Y, Hirota KI, Nagata SI, Tozaki T, Kakoi H, Ishiguro-Oonuma T, Kizaki K.Circulating microRNAs (miRNAs) are stable in bodily fluids and are potential biomarkers of various diseases and physiological states. Although several studies have been conducted on humans to detect drug doping by miRNAs, research on drugs and miRNAs in horses is limited. In this study, circulating miRNAs in horses after hydrocortisone administration were profiled and variations in miRNAs affected by hydrocortisone administration during endogenous hydrocortisone elevation were examined. The miRNAs were extracted from thoroughbred horse plasma before and after hydrocortisone administration and ...
Retrospective study on equine viral abortions in Poland between 1999 and 2022.
Journal of veterinary research    June 16, 2023   Volume 67, Issue 2 155-160 doi: 10.2478/jvetres-2023-0019
Stasiak K, Socha W, Rola J.Loss of pregnancy in mares is a major cause of economic and emotional impact for horse breeders. It can have many different infectious and noninfectious causes. The aim of this study was identification of the main viral causes of abortion in mares in Poland based on tissue samples from 180 aborted foetuses submitted for testing between 1999 and 2022. Unassigned: Tissues of aborted foetuses collected from different horse studs throughout Poland were tested for the presence of equine herpesvirus types 1 and 4 (EHV-1/-4) and if negative, for equine arteritis virus (EAV). The examination was perfo...
Investigation of optimal procedures for storage and use of plasma samples suitable for gene doping tests.
Journal of equine science    June 12, 2023   Volume 34, Issue 2 21-27 doi: 10.1294/jes.34.21
Tozaki T, Ohnuma A, Kikuchi M, Ishige T, Kakoi H, Hirota KI, Takahashi Y, Nagata SI.Gene doping, which is prohibited in horseracing and equestrian sports, can be performed by introducing exogenous genes, known as transgenes, into the bodies of postnatal animals. To detect exogenous genes, a method utilizing quantitative polymerase chain reaction (qPCR) with a hydrolysis probe was developed to test whole blood and plasma samples, thereby protecting the fairness of competition and the rights of stakeholders in horseracing and equestrian sports. Therefore, we aimed to develop sample storage methods suitable for A and B samples in gene doping tests using blood. For sample A, suff...
Relationship between quantitative real-time PCR cycle threshold and culture for detection of Streptococcus equi subspecies equi.
The Canadian veterinary journal = La revue veterinaire canadienne    June 2, 2023   Volume 64, Issue 6 549-552 
Weese JS, Saab M, Moore A, Cai H, McClure JT.To compare PCR and culture results for the detection of subspecies . Respiratory tract samples (N = 158) from horses being tested for Bacterial culture was carried out on samples from which was detected by quantitative real-time PCR. was isolated from 12 (7.6%) samples: 4/9 (44%) samples when the PCR cycle threshold (C) was ≤ 30, 7/30 (23%) when the C was 30.1 to 35, and 1/119 (0.8%) when the C was 35.1 to 40. The highest C sample from a sample that yielded a positive culture was 36.9. The optimal Youden's J value was at a C of 34.2, the same value as determined by number needed to misdi...
Synovial fluid mitochondrial DNA concentration reflects the degree of cartilage damage after naturally occurring articular injury.
Osteoarthritis and cartilage    April 6, 2023   Volume 31, Issue 8 1056-1065 doi: 10.1016/j.joca.2023.03.013
Seewald LA, Sabino IG, Montney KL, Delco ML.To evaluate mitochondrial DNA (mtDNA) release from injured chondrocytes and investigate the utility of synovial fluid mtDNA concentration in early detection of posttraumatic osteoarthritis. We measured mtDNA release using four models of osteoarthritis: in vitro interleukin-1β stimulation of cultured equine chondrocytes, ex vivo mechanical impact of bovine cartilage explants, in vivo mechanical impact of equine articular cartilage, and naturally occurring equine intraarticular fracture. In our in vivo model, one group was treated with an intraarticular injection of the mitoprotective peptide S...
Identification of putative orthologs of clinically relevant antimicrobial peptides in the equine ocular surface and amniotic membrane.
Veterinary ophthalmology    December 7, 2022   Volume 26 Suppl 1, Issue Suppl 1 125-133 doi: 10.1111/vop.13042
Hisey EA, Martins BC, Donnelly CG, Cassano JM, Katzman SA, Murphy CJ, Thomasy SM, Leonard BC.This study aimed to define the antimicrobial peptide (AMP) expression pattern of the equine ocular surface and amniotic membrane using a targeted qPCR approach and 3'Tag-sequencing. It will serve as a reference for future studies of ocular surface innate immunity and amniotic membrane therapies. Methods: A targeted qPCR approach was used to investigate the presence of orthologs for three of the most highly expressed beta-defensins (DEFB1, DEFB4B, and DEFB103A) of the human ocular surface and amniotic membrane in equine corneal epithelium, conjunctiva, and amniotic membrane. 3'Tag-sequencing wa...
Aggrecan, IL-1β, IL-6, and TNF-α profiles in the Articular Cartilage of Miniature Horses with Chondrodysplastic Dwarfism.
Journal of equine veterinary science    April 30, 2021   Volume 103 103643 doi: 10.1016/j.jevs.2021.103643
Basso RM, Andrade DGA, Alves CEF, Laufer-Amorim R, Borges AS, Oliveira-Filho JP.Dwarfism is a skeletal disorder that causes abnormal growth. In Miniature horses, dwarfism can occur as chondrodysplastic dwarfism, an autosomal recessive disorder associated with five mutations (D1, D2, D3*, D4 and c.6465A > T variant) in the aggrecan (ACAN) gene. The aim of this study was to evaluate the expression of aggrecan (at the gene and protein level) and specific cytokines (IL-1β, IL-6, and TNF-α) in the articular cartilage of Miniature horses with chondrodysplastic dwarfism (D4/c.6465A > T genotype). Metatarsal bone samples from eight dwarf Miniature horses were collected fo...
The In Vitro Inhibitory Effect of Sivelestat on Elastase Induced Collagen and Metallopeptidase Expression in Equine Endometrium.
Animals : an open access journal from MDPI    May 16, 2020   Volume 10, Issue 5 863 doi: 10.3390/ani10050863
Amaral A, Fernandes C, Rebordão MR, Szóstek-Mioduchowska A, Lukasik K, Gawronska-Kozak B, Telo da Gama L, Skarzynski DJ, Ferreira-Dias G.Neutrophil extracellular traps (NETs) fight endometritis, and elastase (ELA), a protease found in NETs, might induce collagen type I (COL1) accumulation in equine endometrium. Metallopeptidases (MMPs) are involved in extracellular matrix balance. The aim was to evaluate the effects of ELA and sivelestat (selective elastase inhibitor) on MMP-2 and MMP-9 expression and gelatinolytic activity, as well as the potential inhibitory effect of sivelestat on ELA-induced COL1 in equine endometrium. Endometrial explants from follicular (FP) and mid-luteal (MLP) phases were treated for 24 or 48 h with ELA...
Potential for residual contamination by Streptococcus equi subspp equi of endoscopes and twitches used in diagnosis of carriers of strangles.
Equine veterinary journal    March 2, 2020   Volume 52, Issue 6 884-890 doi: 10.1111/evj.13248
Svonni E, Andreasson M, Fernström LL, Rydén A, Pringle J, Riihimäki M.Endoscopic examinations are essential for diagnosis and treatment of strangles (S equi infection) in horses. However, even after disinfection, endoscopes may retain viable bacteria or bacterial DNA. Twitches are commonly used during endoscopic examinations and can thus also potentially transmit the organism to other horses. Objective: To evaluate the efficacy of different disinfectant methods to eliminate S equi from experimentally contaminated endoscopes and twitches and the effectiveness of field disinfection of endoscopes used in sampling carriers of S equi. Methods: Experimental contami...
Transplacental Transmission of Theileria equi Is Not a Common Cause of Abortions and Infection of Foals in Israel.
Animals : an open access journal from MDPI    February 21, 2020   Volume 10, Issue 2 341 doi: 10.3390/ani10020341
Tirosh-Levy S, Gottlieb Y, Mimoun L, Mazuz ML, Steinman A.Although the main route of transmission of is through tick feeding, transplacental transmission is also possible and may lead to abortion, or to the birth of a sick or carrier foal. The aim of this study was to evaluate the role of as a cause of abortions in Israel and the risk of foals being infected at a young age. Eight aborting mares were serologically evaluated for exposure to via the immunofluorescence antibody test (IFAT) and their aborted fetuses were evaluated using PCR and qPCR. In addition, five mares and their foals (aged 4-6 months) from a highly endemic farm were tested for i...
Tracheal microbial populations in horses with moderate asthma.
Journal of veterinary internal medicine    January 27, 2020   Volume 34, Issue 2 986-995 doi: 10.1111/jvim.15707
Manguin E, Pépin E, Boivin R, Leclere M.There are limited data on potential dysbiosis of the airway microbiota in horses with asthma. Objective: We hypothesized that the respiratory microbiota of horses with moderate asthma is altered. Our objectives were (a) to quantify tracheal bacterial populations using culture and qPCR, (2) to compare aerobic culture and qPCR, and (c) to correlate bacterial populations with bronchoalveolar lavage fluid (BALF) cytology. Methods: Eighteen horses with moderate asthma from a hospital population and 10 controls. Methods: Prospective case-control study. Aerobic culture was performed on tracheal aspir...
Transcriptomic Analysis of Testicular Gene Expression in Normal and Cryptorchid Horses.
Animals : an open access journal from MDPI    January 8, 2020   Volume 10, Issue 1 doi: 10.3390/ani10010102
Han H, Dong H, Chen Q, Gao Y, Li J, Li W, Dang R, Lei C.Testes produce sperm, and investigations into gene expression in the testes will enhance the understanding of the roles of testicular genes in male reproduction. Cryptorchidism, the failure of one or both testes to descend into the scrotal sac, is a common congenital malformation in horses. The major clinical consequence of this abnormality is impaired fertility. The aim of this study was to analyze the expression patterns of testicular genes and to identify the differentially expressed genes (DEGs) in testes between cryptorchid and normal horses. In this study, the gene expression patterns in...
Molecular detection of Streptococcus equi subspecies equi in face flies (Musca autumnalis) collected during a strangles outbreak on a Thoroughbred farm.
Medical and veterinary entomology    July 7, 2019   Volume 34, Issue 1 120-122 doi: 10.1111/mve.12394
Pusterla N, Bowers J, Barnum S, Hall JA.The objective of this study was to detect Streptococcus equi subspecies equi (S. equi) (Lactobacillales: Streptococcaceae) using quantitative polymerase chain reaction (qPCR) in flies collected from a farm with a documented outbreak of strangles. A total of 1856 face flies [Musca autumnalis (Diptera: Muscidae)] were collected using conventional fly traps. The flies were processed for nucleic acid purification and tested for the presence of S. equi by qPCR. A total of 10/1856 flies (0.54%) tested qPCR-positive for S. equi. The results may implicate the presence of face flies as a risk factor...
Isolation of naturally infecting Leishmania infantum from canine samples in Novy-MacNeal-Nicolle medium prepared with defibrinated blood from different animal species.
Veterinary parasitology    May 22, 2018   Volume 257 10-14 doi: 10.1016/j.vetpar.2018.05.010
Santos RCD, Pinho FA, Passos GP, Larangeira DF, Barrouin-Melo SM.The most commonly used culture medium for the in vitro isolation of Leishmania spp. from canine biological samples is biphasic Novy-MacNeal-Nicolle (NNN) medium, whose solid phase is prepared using rabbit blood. Leishmania infantum parasites from natural infections are highly sensitive and demanding for growth in axenic conditions when firstly obtained from the dog's body. The objective of this study was to evaluate whether NNN medium (NNN-test) prepared with chicken blood (NNN-C), ox blood (NNN-O), horse blood (NNN-H) or sheep blood (NNN-S) was viable for the isolation of parasites from natur...
Treatment of limb wounds of horses with orf virus IL-10 and VEGF-E accelerates resolution of exuberant granulation tissue, but does not prevent its development.
PloS one    May 15, 2018   Volume 13, Issue 5 e0197223 doi: 10.1371/journal.pone.0197223
Wise LM, Bodaan CJ, Stuart GS, Real NC, Lateef Z, Mercer AA, Riley CB, Theoret CL.Bandaging of limb wounds in horses leads to formation of exuberant granulation tissue (EGT) that retards healing due to protracted inflammation, aberrant vascularisation and delayed epithelialisation. EGT is not observed if wounds are left undressed or when wounds are on the body. A previous study showed that short-term administration of proteins derived from orf virus dampened inflammation and promoted epithelialisation of open wounds in horses. Here, we investigated the impact of orf virus interleukin-10 and vascular endothelial growth factor-E on the development and resolution of EGT. Excis...
Identification of Reference Genes for Analysis of microRNA Expression Patterns in Equine Chorioallantoic Membrane and Serum.
Molecular biotechnology    December 5, 2017   Volume 60, Issue 1 62-73 doi: 10.1007/s12033-017-0047-2
Dini P, Loux SC, Scoggin KE, Esteller-Vico A, Squires EL, Troedsson MHT, Daels P, Ball BA.MicroRNAs (miRNAs) have important posttranscriptional regulatory abilities, and there is considerable interest in evaluating their expression patterns in different pathophysiological states. The most common method of quantifying miRNA expression is quantitative reverse transcription PCR; however, the identification of tissue-specific and species-specific reference miRNA is a prerequisite for miRNA expression analysis. Currently, no reference genes have been described for evaluating miRNA expression in equine serum and chorioallantoic membrane (CAM) during pregnancy. The aim of the present stud...
The possible role of Stomoxys calcitrans in equine sarcoid transmission.
Veterinary journal (London, England : 1997)    November 22, 2017   Volume 231 8-12 doi: 10.1016/j.tvjl.2017.11.009
Haspeslagh M, Vlaminck L, Martens A.The association between bovine papillomavirus (BPV) and equine sarcoids is well established, but it is unclear how the virus spreads. Although evidence in support of viral spread through direct animal contact exists, this does not explain sarcoid development in isolated equids. BPV DNA has been detected in flies, which could indicate that these insects serve as a vector. This study aimed to investigate whether BPV-negative stable flies (Stomoxys calcitrans) become positive for BPV DNA after exposure to equine sarcoid or bovine papilloma tissue under experimental conditions and, if so, for how ...
Seroprevalence of horses to Coxiella burnetii in an Q fever endemic area.
Veterinary microbiology    November 13, 2017   Volume 215 49-56 doi: 10.1016/j.vetmic.2017.11.012
Desjardins I, Joulié A, Pradier S, Lecollinet S, Beck C, Vial L, Dufour P, Gasqui P, Legrand L, Edouard S, Sidi-Boumedine K, Rousset E, Jourdain E....Coxiella burnetii can infect many animal species, but its circulation dynamics in and through horses is still unclear. This study evaluated horse exposure in an area known to be endemic for ruminants and humans. We assessed antibody prevalence in horse serum by ELISA, and screened by qPCR horse blood, ticks found on horses and dust from stables. Horse seroprevalence was 4% (n = 335, 37 stables) in 2015 and 12% (n = 294, 39 stables) in 2016. Of 199 horses sampled both years, 13 seroconverted, eight remained seropositive, and one seroreverted. Seropositive horses were located close to re...
RNA sample preparation applied to gene expression profiling for the horse biological passport.
Drug testing and analysis    May 31, 2017   Volume 9, Issue 9 1448-1455 doi: 10.1002/dta.2204
Bailly-Chouriberry L, Baudoin F, Cormant F, Glavieux Y, Loup B, Garcia P, Popot MA, Bonnaire Y.The improvement of doping control is an ongoing race. Techniques to fight doping are usually based on the direct detection of drugs or their metabolites by analytical methods such as chromatography hyphenated to mass spectrometry after ad hoc sample preparation. Nowadays, omic methods constitute an attractive development and advances have been achieved particularly by application of molecular biology tools for detection of anabolic androgenic steroids (AAS), erythropoiesis-stimulating agent (ESA), or to control human growth hormone misuses. These interesting results across different animal spe...
Detection and quantification of Cryptosporidium oocysts in environmental surfaces of an Equine Perinatology Unit.
Preventive veterinary medicine    May 27, 2016   Volume 131 67-74 doi: 10.1016/j.prevetmed.2016.04.012
Piva S, Caffara M, Pasquali F, Castagnetti C, Iacono E, Massella E, Zanoni RG, Galuppi R.The presence of Cryptosporidium in institutions such as veterinary teaching hospitals, where students and staff are in frequent contact with animals, could represent a serious public health risk. In this study the detection and quantification of the Cryptosporidium oocysts present on the environmental surfaces of an Equine Perinatology Unit (EPU) were investigated. During 3 foaling seasons 175 samples obtained by swabbing an area of the floor and walls of boxes and utility rooms of EPU with sterile gauze, in 3 different moments. Samples were collected at the end of foaling season (July), after...
Transcriptomic profile adaptations following exposure of equine satellite cells to nutriactive phytochemical gamma-oryzanol.
Genes & nutrition    March 17, 2016   Volume 11 5 doi: 10.1186/s12263-016-0523-5
Szcześniak KA, Ciecierska A, Ostaszewski P, Sadkowski T.Adult skeletal muscle myogenesis depends on the activation of satellite cells that have the potential to differentiate into new fibers. Gamma-oryzanol (GO), a commercially available nutriactive phytochemical, has gained global interest on account of its muscle-building and regenerating effects. Here, we investigated GO for its potential influence on myogenesis, using equine satellite cell culture model, since the horse is a unique animal, bred and exercised for competitive sport. To our knowledge, this is the first report where the global gene expression in cultured equine satellite cells has ...
In vitro screening of mare’s milk antimicrobial effect and antiproliverative activity.
FEMS microbiology letters    December 9, 2015   Volume 363, Issue 2 fnv234 doi: 10.1093/femsle/fnv234
Guri A, Paligot M, Crèvecoeur S, Piedboeuf B, Claes J, Daube G, Corredig M, Griffiths MW, Delcenserie V.The aims of this study were to examine the effect of mare's milk on virulence gene expression of Salmonella Typhimurium and observe its potential activity on proliferation of adenocarcinoma Caco-2 cells. Different supernatants of mare's milk, raw or heat-treated at 65°C for 15 s or 30 min, were studied. The changes in hilA gene expression of Salmonella Typhimurium in presence of mare's milk supernatants were assessed using a reporter luminescent strain. A significant decrease in hilA gene expression was observed with all tested supernatants. Virulence gene expression was then assessed using q...
Molecular evidence of Theileria equi infection in Hyalomma anatolicum ticks infested on sero-positive Indian horses.
Acta parasitologica    July 24, 2015   Volume 60, Issue 2 322-329 doi: 10.1515/ap-2015-0045
Bhagwan J, Kumar A, Kumar R, Goyal L, Goel P, Kumar S.A sizeable Indian equine population is considered to be pre-immune carrier of Theileria equi infection. In this study we confirmed the presence of T. equi specific DNA in Hyalomma anatolicum ticks which were infested on sero-positive horses. Fifty two Indigenous horses were randomly selected from endemic areas and their blood and tick samples were collected. Tick salivary glands and blood samples were processed for separation of DNA and serum, respectively. Serum samples were analyzed by EMA-2ELISA and nine horses were found positive for T. equi specific antibodies. Species-specific primers we...
Detection of modified-live equine intranasal vaccine pathogens in adult horses using quantitative PCR.
The Veterinary record    October 1, 2014   Volume 175, Issue 20 510 doi: 10.1136/vr.102592
Harms C, Mapes S, Akana N, Coatti Rocha D, Pusterla N.No abstract available
Transcriptome profiling of granulosa and theca cells during dominant follicle development in the horse.
Biology of reproduction    September 24, 2014   Volume 91, Issue 5 111 doi: 10.1095/biolreprod.114.118943
Donadeu FX, Fahiminiya S, Esteves CL, Nadaf J, Miedzinska K, McNeilly AS, Waddington D, Gérard N.Several aspects of equine ovarian physiology are unique among domestic species. Moreover, follicular growth patterns are very similar between horses and humans. This study aimed to characterize, for the first time, global gene expression profiles associated with growth and preovulatory (PO) maturation of equine dominant follicles. Granulosa cells (GCs) and theca interna cells (TCs) were harvested from follicles (n = 5) at different stages of an ovulatory wave in mares corresponding to early dominance (ED; diameter ≥22 mm), late dominance (LD; ≥33 mm) and PO stage (34 h after administration...
Inhaled corticosteroids modulate the (+)insert smooth muscle myosin heavy chain in the equine asthmatic airways.
Thorax    September 9, 2014   Volume 69, Issue 12 1113-1119 doi: 10.1136/thoraxjnl-2014-205572
Boivin R, Vargas A, Lefebvre-Lavoie J, Lauzon AM, Lavoie JP.Overexpression of the (+)insert smooth muscle myosin heavy chain (SMMHC) isoform could contribute to airway bronchospasm by increasing the velocity of contraction. Whether the (+)insert isoform is present in the small airways and its expression is reversible in asthma are unknown. Objective: To determine the anatomical location and the expression kinetics of the (+)insert SMMHC isoform in airways of horses with heaves and to evaluate its modulation in response to disease status. Methods: We evaluated the (+)insert SMMHC isoform in the airways of horses with heaves during disease exacerbation a...
Dexamethasone acutely down-regulates genes involved in steroidogenesis in stallion testes.
The Journal of steroid biochemistry and molecular biology    July 7, 2014   Volume 143 451-459 doi: 10.1016/j.jsbmb.2014.07.003
Ing NH, Forrest DW, Riggs PK, Loux S, Love CC, Brinsko SP, Varner DD, Welsh TH.In rodents, livestock and primate species, a single dose of the synthetic glucocorticoid dexamethasone acutely lowers testosterone biosynthesis. To determine the mechanism of decreased testosterone biosynthesis, stallions were treated with 0.1mg/kg dexamethasone 12h prior to castration. Dexamethasone decreased serum concentrations of testosterone by 60% compared to saline-treated control stallions. Transcriptome analyses (microarrays, northern blots and quantitative PCR) of testes discovered that dexamethasone treatment decreased concentrations of glucocorticoid receptor alpha (NR3C1), alpha a...