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Schuler G. [Induction and endocrine control of parturition in domestic mammals - Part 2 - Species-specific aspects and their relevance to the applicability of birth induction procedures]. Tierarztl Prax Ausg G Grosstiere Nutztiere 2023; 51:377-385. [PMID: 37903595 DOI: 10.1055/a-2142-3333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
The endocrine regulation of birth is based on an intensive exchange of signals between fetus, placenta and mother. Apart from sheep, our knowledge of the underlying processes is still very incomplete. However, current observations suggest substantial species differences. Of critical importance for the onset of the final steps of the signaling cascade leading to active labor is "prepartum progesterone withdrawal," which is based on luteolysis (e. g., cattle, goat, buffalo, camelids, pig) or a breakdown in placental progestogen production (sheep, horse), depending on the relevant progestogen source in late pregnancy. Knowledge of birth-associated regulatory processes allows species-specific regulatory mechanisms to be mimicked for drug-based induction of labor. Furthermore, species-independent mechanisms such as the inhibition of progesterone receptors are available. In addition to efficacy, other aspects such as tolerability for dams and offspring as well as drug regulations must be taken into account when selecting active ingredients under practical conditions.
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Affiliation(s)
- Gerhard Schuler
- Tierklinik für Reproduktionsmedizin und Neugeborenenkunde, Justus-Liebig-Universität Giessen
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Nagel C, Aurich C. Induction of parturition in horses - from physiological pathways to clinical applications. Domest Anim Endocrinol 2022; 78:106670. [PMID: 34517269 DOI: 10.1016/j.domaniend.2021.106670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 11/03/2022]
Abstract
Based on the marked variability in physiological equine gestation length, induction of foaling in mares often results in the birth of dysmature foals. Precise prediction of preparedness of the mare for foaling is thus essential. Treatment with glucocorticoids mimics the fetal signal that initiates birth. Repeated daily dexamethasone treatment in late gestation results in birth of mature foals but the time from initiation of treatment to foaling is highly variable and complications such as dystocia have been reported. Contrary to most expectations, treatment of prepartum mares with progestogens does not delay but advances the onset of foaling. Prostaglandin F2α (PGF2α) and its analogues are effective to induce foaling but even in mares ready for parturition, foal health remains to some extent unpredictable. This may be caused by a relatively long interval between PGF2α treatment and birth, exposing the fetus for several hours to uterine contractions. Oxytocin reliably induces foaling towards the end of pregnancy, but when given at high doses is effective also in the pre-viable period of gestation, resulting in birth of premature foals. Recent research has focused on reducing the amount of oxytocin with the aim to induce foaling only in mares prepared for foaling. Mares selected on clinical criteria receive 1 dose of 2.5 to 3.5 IU of oxytocin. Mares not responding to oxytocin are judged not yet ready for foaling and treatment is repeated the earliest after 24 h. This protocol at present is the most reliable and safest way to induce parturition in mares.
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Affiliation(s)
- C Nagel
- Graf Lehndorff Institute for Equine Science, Vetmeduni Vienna, Hauptgestüt, 1016845 Neustadt(Dosse), Germany.
| | - C Aurich
- Department for Small Animals and Horses, Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Veterinärplatz 1, 1210 Vienna, Austria
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Affiliation(s)
- S. L. Jalim
- Victorian Equine Group White Hills Victoria Australia
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Legacki EL, Ball BA, Corbin CJ, Loux SC, Scoggin KE, Stanley SD, Conley AJ. Equine fetal adrenal, gonadal and placental steroidogenesis. Reproduction 2017; 154:445-454. [DOI: 10.1530/rep-17-0239] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/03/2017] [Accepted: 07/10/2017] [Indexed: 11/08/2022]
Abstract
Equine fetuses have substantial circulating pregnenolone concentrations and thus have been postulated to provide significant substrate for placental 5α-reduced pregnane production, but the fetal site of pregnenolone synthesis remains unclear. The current studies investigated steroid concentrations in blood, adrenal glands, gonads and placenta from fetuses (4, 6, 9 and 10 months of gestational age (GA)), as well as tissue steroidogenic enzyme transcript levels. Pregnenolone and dehydroepiandrosterone (DHEA) were the most abundant steroids in fetal blood, pregnenolone was consistently higher but decreased progressively with GA. Tissue steroid concentrations generally paralleled those in serum with time. Adrenal and gonadal tissue pregnenolone concentrations were similar and 100-fold higher than those in allantochorion. DHEA was far higher in gonads than adrenals and progesterone was higher in adrenals than gonads. Androstenedione decreased with GA in adrenals but not in gonads. Transcript analysis generally supported these data.CYP17A1was higher in fetal gonads than adrenals or allantochorion, andHSD3B1was higher in fetal adrenals and allantochorion than gonads.CYP11A1transcript was also significantly higher in adrenals and gonads than allantochorion andCYP19and SRD5A1 transcripts were higher in allantochorion than either fetal adrenals or gonads. Given these data, and their much greater size, the fetal gonads are the source of DHEA and likely contribute more than fetal adrenal glands to circulating fetal pregnenolone concentrations. LowCYP11A1but highHSD3B1andSRD5A1transcript abundance in allantochorion, and low tissue pregnenolone, suggests that endogenous placental pregnenolone synthesis is low and likely contributes little to equine placental 5α-reduced pregnane secretion.
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Conley A. Review of the reproductive endocrinology of the pregnant and parturient mare. Theriogenology 2016; 86:355-65. [DOI: 10.1016/j.theriogenology.2016.04.049] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/16/2016] [Accepted: 03/14/2016] [Indexed: 10/21/2022]
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Fowden AL, Valenzuela OA, Vaughan OR, Jellyman JK, Forhead AJ. Glucocorticoid programming of intrauterine development. Domest Anim Endocrinol 2016; 56 Suppl:S121-32. [PMID: 27345310 DOI: 10.1016/j.domaniend.2016.02.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 02/11/2016] [Accepted: 02/29/2016] [Indexed: 12/26/2022]
Abstract
Glucocorticoids (GCs) are important environmental and maturational signals during intrauterine development. Toward term, the maturational rise in fetal glucocorticoid receptor concentrations decreases fetal growth and induces differentiation of key tissues essential for neonatal survival. When cortisol levels rise earlier in gestation as a result of suboptimal conditions for fetal growth, the switch from tissue accretion to differentiation is initiated prematurely, which alters the phenotype that develops from the genotype inherited at conception. Although this improves the chances of survival should delivery occur, it also has functional consequences for the offspring long after birth. Glucocorticoids are, therefore, also programming signals that permanently alter tissue structure and function during intrauterine development to optimize offspring fitness. However, if the postnatal environmental conditions differ from those signaled in utero, the phenotypical outcome of early-life glucocorticoid receptor overexposure may become maladaptive and lead to physiological dysfunction in the adult. This review focuses on the role of GCs in developmental programming, primarily in farm species. It examines the factors influencing GC bioavailability in utero and the effects that GCs have on the development of fetal tissues and organ systems, both at term and earlier in gestation. It also discusses the windows of susceptibility to GC overexposure in early life together with the molecular mechanisms and long-term consequences of GC programming with particular emphasis on the cardiovascular, metabolic, and endocrine phenotype of the offspring.
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Affiliation(s)
- A L Fowden
- Centre for Trophoblast and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK.
| | - O A Valenzuela
- Centre for Trophoblast and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - O R Vaughan
- Centre for Trophoblast and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - J K Jellyman
- Centre for Trophoblast and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK; Department of Obstetrics and Gynecology, Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles Medical Center, Torrance, CA 90502, USA
| | - A J Forhead
- Centre for Trophoblast and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK; Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
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Cuming RS, Groover ES, Wooldridge AA, Caldwell FJ. Review of glucocorticoid therapy in horses. Part 1: Pharmacology. EQUINE VET EDUC 2016. [DOI: 10.1111/eve.12555] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- R. S. Cuming
- J. T. Vaughan Large Animal Teaching Hospital Auburn University Alabama USA
| | - E. S. Groover
- J. T. Vaughan Large Animal Teaching Hospital Auburn University Alabama USA
| | - A. A. Wooldridge
- J. T. Vaughan Large Animal Teaching Hospital Auburn University Alabama USA
| | - F. J. Caldwell
- J. T. Vaughan Large Animal Teaching Hospital Auburn University Alabama USA
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Valenzuela OA, Jellyman JK, Allen VL, Holdstock NB, Fowden AL. Effects of maternal dexamethasone treatment on pancreatic β cell function in the pregnant mare and post natal foal. Equine Vet J 2016; 49:99-106. [DOI: 10.1111/evj.12560] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 12/11/2015] [Indexed: 01/06/2023]
Affiliation(s)
- O. A. Valenzuela
- Department of Physiology, Development and Neuroscience; University of Cambridge; CB2 3EG UK
| | - J. K. Jellyman
- Department of Physiology, Development and Neuroscience; University of Cambridge; CB2 3EG UK
| | - V. L. Allen
- Department of Physiology, Development and Neuroscience; University of Cambridge; CB2 3EG UK
| | - N. B. Holdstock
- Department of Clinical Veterinary Medicine; University of Cambridge; CB2 3EG UK
| | - A. L. Fowden
- Department of Physiology, Development and Neuroscience; University of Cambridge; CB2 3EG UK
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Castagnetti C, Mariella J. Anti-inflammatory Drugs in Equine Neonatal Medicine. Part II: Corticosteroids. J Equine Vet Sci 2015. [DOI: 10.1016/j.jevs.2015.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Jellyman JK, Valenzuela OA, Fowden AL. HORSE SPECIES SYMPOSIUM: Glucocorticoid programming of hypothalamic-pituitary-adrenal axis and metabolic function: Animal studies from mouse to horse1,2. J Anim Sci 2015; 93:3245-60. [DOI: 10.2527/jas.2014-8612] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J. K. Jellyman
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502
| | - O. A. Valenzuela
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - A. L. Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
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Fowden AL, Jellyman JK, Valenzuela OA, Forhead AJ. Nutritional Programming of Intrauterine Development: A Concept Applicable to the Horse? J Equine Vet Sci 2013. [DOI: 10.1016/j.jevs.2013.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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FOWDEN AL, FORHEAD AJ, OUSEY JC. Endocrine adaptations in the foal over the perinatal period. Equine Vet J 2012:130-9. [DOI: 10.1111/j.2042-3306.2011.00505.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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WRIGHT S. Highlights of recent clinically relevant papers. EQUINE VET EDUC 2011. [DOI: 10.1111/j.2042-3292.2011.00309.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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