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Topic:Steroid Hormones
Steroid hormones in horses are biologically active compounds that are synthesized from cholesterol and play a significant role in various physiological processes. These hormones include glucocorticoids, mineralocorticoids, and sex steroids such as estrogens, androgens, and progestogens. They are involved in regulating metabolism, immune function, electrolyte balance, and reproductive functions. The levels of steroid hormones can be influenced by factors such as age, sex, stress, and disease states. Understanding their regulatory mechanisms and effects is essential for managing equine health and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the synthesis, regulation, and physiological roles of steroid hormones in horses.
Lipidomics and biochemical profiling of adult Yili horses in a 26 km endurance race: exploring metabolic adaptations. The equine lipid metabolism is activated during and after endurance exercise to provide energy in response to the metabolic and physiological changes in the body caused by prolonged exercise; however, the specific regulatory mechanisms remain controversial and identifying differential lipid metabolites associated with equine endurance is essential to elucidate these regulatory mechanisms. In this study, blood samples for lipid metabolomic analysis and biochemical indices were collected before and after a 26 km race from 12 Yili horses with different endurance performance. The biochemical res...
Endogenous Nature of Hydrocortisone Acetate in Horse. 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.
Corticosteroid Administration Enhances the Glycemic, Insulinemic, and Incretin Responses to a High-Protein Mixed Meal in Adult Horses. Corticosteroids are used routinely in horses and induce insulin dysregulation (ID). Nutrition is important for ID management and includes low nonstructural carbohydrate (NSC) diets and, often, high-protein ration balancers (RB). Insulin and incretin secretion increase after high-protein meals; corticosteroids may influence these effects. Objective: A high-protein mixed meal will induce hyperinsulinemia and increased concentrations of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) in horses with ID; dexamethasone (DEX) will amplify this effect. Methods: F...
Late gestation maternal overnutrition alters gene expression and histomorphology in neonatal foal testes. Reproductive health of male offspring following perturbations in maternal nutrition is not well-described in the horse; therefore, the objective of this study was to determine the effects of maternal overnutrition on neonatal foal testicular development. Sixteen Quarter Horse mares were used in a completely randomized design and stratified by expected foaling date, body weight, and body condition score into 1 of 2 dietary treatments beginning on gestational day 235: control (CON; n = 8) fed to meet nutrient requirements and overfed (HIGH; n = 8) fed 40% above CON. At 5 h postpartum, f...
Dexamethasone administration transiently increases insulin response to an oral carbohydrate challenge in horses. Dexamethasone is used to experimentally induce insulin resistance; however, its impact on insulin secretion is unclear. This study aimed to assess the responses to oral carbohydrate challenges in dexamethasone-treated horses. Unassigned: 8 healthy Standardbreds received 0.08 mg/kg of dexamethasone IM every 48 hours for 14 days in June 2022 (winter in the Southern hemisphere). Oral glucose tests (OGT) were conducted before treatment (day 1) and on days 8 and 15. Glucose, insulin, triglycerides, total and active glucagon-like peptide-1 (tGLP-1 and aGLP-1) and glucose-dependent insulinotropic pol...
From Pre-Foaling to Late Pregnancy: Cortisol, DHEA(S), Progesterone, 17-β-Estradiol, and Allopregnanolone Hair Concentration Profiles in Standardbred Mares. Pregnancy and parturition represent two important physiologic phases in female mammals, in which metabolic, behavioral, and endocrinologic changes should occur in perfect timing and interaction, leading to a normal course of gestation and the occurrence of parturition at term, allowing the birth of mature and viable offspring. The present study aimed to describe the hormonal changes recorded in the hair occurring in mares from pre-foaling to late pregnancy. The hair cortisol (C) concentrations did not show any significant variations throughout the study, while dehydroepiandrosterone (sulfate) ...
Granulosa cell function in domestic animals: A review on the in vitro effects of FSH, insulin and insulin-like growth factor 1. Ovarian granulosa cells produce a variety of biologically active compounds in addition to steroid hormones that include numerous families of growth factors, cytokines and adipokines. Many of these function as endocrine, paracrine and autocrine hormones to regulate ovarian activity. The goal of this review is to provide an update on the evidence in domestic animals on how FSH, insulin and IGF1 regulate the function of granulosa cells with a focus on ovarian steroidogenesis and cell proliferation with comparisons across six domestic animals: pigs, cattle, horses, water buffalo, goats and sheep. ...
Evaluation of a non-radioactive rapid test for the determination of serum progesterone in the mare. The determination of progesterone from mares' serum plays a decisive role in diagnosing estrus cycle disorders or luteal insufficiency. To date, no measurement methods are available for rapid quantitative diagnosis of serum progesterone in the mare that would allow results to be available within a two-hour time frame. The present study will evaluate a commercial enzyme-linked fluorescent assay, the mini VIDAS device (bioMérieux, Nürtingen, Germany). Serum was prepared from the blood samples of one hundred and seven mares, divided into two aliquots, and stored at -20°C. Subsequently, compara...
Effect of furosemide on comprehensive renin-angiotensin-aldosterone system activity of Thoroughbred horses. Furosemide, a commonly used diuretic, activates the renin-angiotensin-aldosterone system (RAAS) in other species. Little is known about RAAS peptide activation in horses. Objective: To evaluate equilibrium analysis as a practical method for RAAS quantification in horses and describe the RAAS response to a single dose of furosemide. We hypothesize that furosemide would cause transient increase in RAAS peptides in horses. Methods: 14 healthy adult thoroughbreds from a university teaching herd. Methods: Horses received either furosemide (1 mg/kg IV) or saline IV in a crossover study design. Pro...
Administration Route Differentiation of Altrenogest via the Metabolomic LC-HRMS Analysis of Equine Urine. Altrenogest, also known as allyltrenbolone, is a synthetic form of progesterone used therapeutically to suppress unwanted symptoms of estrus in female horses. Altrenogest affects the system by decreasing levels of endogenous gonadotrophin and luteinizing and follicle-stimulating hormones, which in turn decreases estrogen and mimics the increase of progesterone production. This results in more manageable mares for training and competition alongside male horses while improving the workplace safety of riders and handlers. However, when altrenogest is administered, prohibited steroid impurities su...
Sex hormone-binding globulin promotes the osteogenic differentiation potential of equine adipose-derived stromal cells by activating the BMP signaling pathway. Musculoskeletal injuries and chronic degenerative diseases pose significant challenges in equine health, impacting performance and overall well-being. Sex Hormone-Binding Globulin (SHBG) is a glycoprotein determining the bioavailability of sex hormones in the bloodstream, and exerting critical metabolic functions, thus impacting the homeostasis of many tissues including the bone. Unassigned: In this study, we investigated the potential role of SHBG in promoting osteogenesis and its underlying mechanisms in a model of equine adipose-derived stromal cells (ASCs). An SHBG-knocked down model has b...
Pharmacokinetics of Two Formulations of Altrenogest Administered to Mares. Altrenogest is a synthetic progestin that suppresses reproductive behaviours and assists pregnancy maintenance in female horses. Two formulations are available, a 'weekly' intramuscular injection and a daily oral formulation. Altrenogest administration has returned positive swabs for steroids; consequently, using injectable altrenogest in racing mares is prohibited. Oral administration may be permitted in race mares if there is one clear day between dosing and racing. The only pharmacokinetic data available were generated from geldings. Therefore, to assist veterinarians and analysts in determ...
Can the reduced GH, IGF-1, and ovarian steroids concentrations be considered as suspected biomarkers of age-associated functional deficit in mares? In humans' and experimental animals' components of the somatotropic axis, such as growth hormone (GH) and insulin-like growth factor 1 (IGF-1) concentrations, decrease with advancing age. Although there is evidence regarding IGF-1, the effect of age on GH in mares, as well as the relationships between both parameters, have not yet been elucidated. On the other hand, although GH and IGF-1 are related to follicular development, it is unknown if they could be correlated with the circulating concentrations of ovarian steroids in mares, as occurs in other species. The hypothesis of this study was t...
Application of blood parameters for the early diagnosis of natural ascending placentitis in pregnant mares. Placental infection is an important cause of late-term pregnancy loss and neonatal diseases in horses. Detection of changes in blood parameters especially during early placentitis could improve the diagnostic accuracy, treatment decision, and potential outcomes. The objectives of this 2-part study were to identify differences in circulating immunological, inflammatory, and hormonal parameters between mares with natural ascending placentitis and control mares; evaluate each and combination of parameters as predictors of placentitis; and determine how these parameters indicate severity of placen...
Detection of nonsteroidal and steroidal selective androgen receptor modulators in equine hair after oral administrations. This paper describes the detections of nonsteroidal and steroidal selective androgen receptor modulators (SARMs), namely, RAD140 and YK-11, in mane hair collected from horses having been orally administered with the respective drugs. SARMs are potent anabolic agents with a high potential of misuse in horseracing and equestrian sports, and the misuses of RAD140 and YK-11 in human sports have been reported. To better control the misuse of RAD140 and YK-11 in horses, two separate oral administration studies of RAD140 (0.3Â mg/kg daily for 3Â days) and YK-11 (0.2Â mg/kg daily for 3Â days) were pre...
Detection of the selective androgen receptor modulator S-23 and its metabolites in equine urine and plasma following oral administration. S-23 is an arylpropionamide selective androgen receptor modulator that has been investigated in animal models for use as a male hormonal contraceptive but is not yet available therapeutically. S-23 is available alongside other selective androgen receptor modulators (SARMs) to purchase online via uncontrolled sites, sold as supplement products. It has been detected in several human doping cases, highlighting the importance of identifying the best analytical targets for equine doping control. The purpose of this study was to investigate the detection of S-23 and its phase I metabolites in equine...
Doping control of estra-4,9-diene-3,17-dione in horses. Estra-4,9-diene-3,17-dione (dienedione) is an anabolic-androgenic steroid (AAS) available on the market as a dietary supplement for bodybuilding. It is prohibited in both human and equine sports due to its potential performance-enhancing effect. With the rare presence of the 4,9-diene configuration in endogenous steroids, dienedione has been considered as a synthetic AAS. Nevertheless, the reoccurring detection of dienedione in entire male horse urine samples led to the investigation of its possible endogenous nature in horses, and its endogenous nature in entire male horses has been recently ...
Induction of in vivo-like ciliation in confluent monolayers of re-differentiated equine oviduct epithelial cells. We recently developed re-differentiated equine oviduct epithelial cell (REOEC) monolayers demonstrating various in vivo morphological characteristics, but lacking secondary ciliation. In this study, we evaluated the effects of fetal bovine serum, reproductive steroid hormones, Wnt- and Notch ligands and inhibitors, and different EOEC seeding densities, in both conventional wells and on microporous membranes, on EOEC morphology and, in particular, secondary ciliation. REOEC monolayers were assessed by confocal microscopy after combined staining of nuclei, cilia and the cytoskeleton. Only Wnt li...
Limited association between stallion-like behavior and hormonal indicators of testicular remnants in geldings. Persistent stallion-like behavior is a common sign of cryptorchidism in supposed geldings. The presence of testicular tissue can be evaluated by analyzing hormones such as testosterone and anti-Müllerian hormone (AMH). Here, we used hormonal analysis to investigate relationships between the likely presence of testicular tissue and stallion-like behavior in samples submitted from presumptive geldings (n = 1,202), retrospectively. Most geldings with stallion-like behaviors had serum concentrations of testosterone (851/1,056; 80.6 %) and AMH (682/877; 77.8 %) below the laboratory reference range...
[Individual hormonal profiles of blood progesterone and estradiol-17β during the course of a reproductive cycle in mares]. This study presents the individual course of estradiol-17ß and progesterone concentrations in blood during the reproductive cycle in mares in order to point out physiological differences between individual animals and to aid in the interpretation of hormone values. Methods: Concentrations of estradiol-17ß and progesterone were determined in seven mares over the course of their cycle. One mare was excluded from the study due to a physiologically deviating cycle. In addition, the mares' ovaries were examined via ultrasound on a daily basis in order to match the hormone values to morphological ...
Endogenous nature of estra-4,9-diene-3,17-dione in entire male horses. Estra-4,9-diene-3,17-dione (dienedione) is an anabolic androgenic steroid (AAS) sold as a bodybuilding supplement. It is prohibited in both human and equine sports. With no report of 4,9-diene configuration in endogenous steroids, dienedione has long been considered a synthetic AAS. Nevertheless, the reoccurring detection of dienedione in colt (entire male horse) urine samples lead to the investigation of its possible endogenous nature in horses. This paper describes (i) the detection of naturally occurring dienedione in colts, (ii) the conjugation study of dienedione and (iii) the population ...
Analysis of gene and protein expression in the endometrium for validation of an ex vivo model of the equine uterus using PCR, digital and visual histopathology. In the past, most research in equine reproduction has been performed in vivo but the use of in vitro and ex vivo models has recently increased. This study aimed to evaluate the functional stability of an ex vivo hemoperfused model for equine uteri with molecular characterization of marker genes and their proteins. In addition, the study validated the respective protein expression and the aptness of the software QuPath for identifying and scoring immunohistochemically stained equine endometrium. After collection, uteri (n = 12) were flushed with preservation solution, transported to the labor...
An extensive screening method for the identification and quantitation of ecdysteroids in equine urine and plasma using liquid chromatography coupled with mass spectrometry. Recently, there has been a report suggesting that ecdysteroids can enhance sports performance, making them relevant substances in doping control. Hence, it is imperative to examine the analytical characteristics of ecdysteroids in biological samples to identify their misuse in competitive sports. Methods: To assess the doping of ecdysteroids such as ecdysone, ecdysterone, ponasterone A, turkesterone, and ajugasterone C, a fast and sensitive extraction and detection method was developed, optimized, and validated using equine urine and plasma. Different extraction techniques, namely, solid-phase...
Hair Cortisol and Testosterone Concentrations in Relation to Maturity and Breeding Status of Male Feral Horses. Steroid-hormone concentrations from non-invasively obtained biomarkers, like hair, can provide a representation of circulating hormones diffused over relatively long time periods (e.g., weeks or months). The hormone cortisol is often associated with physiological or even psychological stress, while testosterone is strongly associated with male development and reproductive success. Increasingly, studies are using hormone levels derived from hair to make inferences among both domestic animals and wildlife. For horses, all previous hair hormone analysis has been done on companion or working anima...
A review of current chemistry, pharmacology, and regulation of endogenous anabolic steroids testosterone, boldenone, and nandrolone in horses. Anabolic androgenic steroids are synthetic substances related to the male sex hormones (androgens). These agents promote the growth of skeletal muscle (anabolic effects) and the development of male sexual characteristics (androgenic effects). Anabolic steroids have been illegally used for many years as performance-enhancing drugs in human, equine, and canine sports and as growth promoters in livestock reared to provide meat for human consumption. The analytical challenge to developing effective means of control within these fields has been exacerbated by the reported endogenous nature of some ...
Investigation of in vitro generated metabolites of GLPG0492 using equine liver microsomes for doping control. An effective alternative to testosterone therapy is selective androgen receptor modulators, a class of compounds that has a tissue-specific effect on muscle and bone. These drugs, which enhance performance, pose a severe abuse risk in competitive sports. GLPG0492 is one of the selective androgen receptor modulators discovered in recent decades. This compound has a unique tissue-specific action for muscle and bone against steroid receptors and acts as a partial agonist for androgen receptors. This study examined GLPG0492 and its metabolites in vitro using equine liver microsomes. Liquid chromat...
Developmental toxicity and transcriptome analysis of equine estrogens in developing medaka (Oryzias latipes) using nanosecond pulsed electric field incorporation. Equine estrogens (EQs) are steroidal hormones isolated from the urine of pregnant mares and are used in the formulation of human medications. This study initially investigated the embryonic developmental toxicity of equilin (Eq) and equilenin (Eqn) in medaka (Oryzias latipes). Malformations were observed in embryos exposed to nominal concentrations of 1 and 10Â mg/L of Eq and Eqn. Delayed hatching was observed at 1Â mg/L of Eq. To further investigate the molecular mechanism of developmental toxicity caused by Eq and Eqn, transcriptome and bioinformatics analyses were performed. Among 2016 and ...
Postnatal Dynamics of Circulating Steroid Hormones in Mule and Equine Neonates. It is necessary to study hormonal patterns from mules to recognize alterations and neonatal maladaptation. Our objective was to evaluate concentrations of hormones in mule (n = 6) and equine foals (n = 6). Blood was collected at T0, 1, 6 and 12 h after birth. Hormone concentrations were evaluated using liquid chromatography tandem mass spectrometry. Effects of time, group and interactions and regression analysis were evaluated (p < 0.05). There was a cubic and quadratic decline in mule and equine foals, respectively, for 3β,20α-dihydroxy-DHP. Mule foals were born with lower circulating 3Î...
Longitudinal assessment of adrenocortical steroid and steroid precursor response to illness in hospitalized foals. Sepsis is a major cause of morbidity and mortality in neonatal foals. Relative adrenal insufficiency (RAI), defined as an inadequate cortisol response to stress, has been associated with sepsis, prematurity, and poor outcome in newborn foals. In addition to cortisol, the adrenal gland synthesizes several biologically important steroids and steroid precursors, including aldosterone, androgens, and progestogens. However, concentration of these hormones during hospitalization and their association with the severity of disease and mortality in critically ill foals have not been completely evaluate...
Tribulus terrestris can suppress the adverse effect of toluene on bovine and equine ovarian granulosa cells. Influence of oil-related product toluene and herbal remedy puncturevine Tribulus terrestris L. (TT) on female reproduction is known. Yet, mechanisms of their action on ovaries in different species and potential protective effect of TT against adverse toluene action remain to be established. We studied the effect of toluene, TT, and their combination on ovarian granulosa cells from two mammalian species (cows and horses). Viability, markers of proliferation (PCNA) and apoptosis (bax), steroid hormones, IGF-I, oxytocin, and prostaglandin F (PGF) release were analyzed by trypan blue exclusion tes...
