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Chavatte-Palmer P, Derisoud E, Robles M. Pregnancy and placental development in horses: an update. Domest Anim Endocrinol 2022; 79:106692. [PMID: 34823139 DOI: 10.1016/j.domaniend.2021.106692] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/03/2022]
Abstract
Horses have been domesticated by man and historical information mostly associates horses with men. Nowadays, however, horse riding is essentially by women. Women are also very much involved in equine sciences, with a large contribution to the understanding of fetoplacental development. While highlighting the work of female scientists, this review describes the recent advances in equine fetoplacental studies, focusing on data obtained by new generation sequencing and progress on the understanding of the role of placental progesterone metabolites throughout gestation. A second emphasis is made on fetal programming, a currently very active field, where the importance of maternal nutrition, mare management or the use of embryo technologies has been shown to induce long term effects in the offspring that might affect progeny's performance. Finally, new perspectives for the study of equine pregnancy are drawn, that will rely on new methodologies applied to molecular explorations and imaging.
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Affiliation(s)
- P Chavatte-Palmer
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France.
| | - E Derisoud
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France
| | - M Robles
- Université Paris-Saclay, UVSQ, INRAE, BREED, Jouy-en-Josas 78350, France; Ecole Nationale Vétérinaire d'Alfort, BREED, Maisons-Alfort 94700, France; INRS Centre Armand-Frappier Santé Biotechnologie, Laval, Québec H7V1B7, Canada
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Turkmen S, Bäckström T, Kangas Flodin Y, Bixo M. Neurosteroid involvement in threatened preterm labour. Endocrinol Diabetes Metab 2021; 4:e00216. [PMID: 33855217 PMCID: PMC8029533 DOI: 10.1002/edm2.216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/25/2020] [Accepted: 11/28/2020] [Indexed: 12/02/2022] Open
Abstract
Introduction The neurosteroid allopregnanolone modulates oxytocin expression in the brain, and its effects arise from its action on the GABAA receptor. Whether neurosteroid levels and the function of the GABAA receptor are involved in the risk of preterm labour in pregnant women is unknown. Methods Pregnant women with (n = 16) or without (n = 20) threatened preterm labour (TPL) in gestational week 33 + 6 days to 37 + 0 days were studied prospectively with procedures including foetal heart rate monitoring, vaginal examination, ultrasound examination and blood tests to determine allopregnanolone, progesterone and oxytocin levels. The GABAA receptor function in both groups was measured with a saccadic eye velocity test (SEVT). Results Plasma oxytocin levels were higher in the TPL group than in the control group (41.5 vs. 37.0 pmol/L, respectively, p = .021). Although the allopregnanolone and progesterone levels in both groups did not differ, there was a negative association between blood oxytocin and allopregnanolone (as predictor) levels in the TPL group (B: -3.2, 95% confidence interval (CI): -5.5 to -0.9, p = .012). As a predictor of TPL, progesterone was associated with cervix maturity (odds ratio: 1.02, 95% CI: 1.00-1.04, p = .038). SEVT showed that the women in both groups had similar GABAA receptor functions. In both groups, body mass index correlated with peak saccadic eye velocity (r = .34, p = .044) and negatively with allopregnanolone (r = -.41, p = .013). Conclusions Neurosteroid levels were unchanged in the peripheral blood of women with TPL, despite the increase in available oxytocin. Although the function of the GABAA receptor was unchanged in women with TPL, to ensure reliable results, saccadic eye velocity should be investigated during a challenge test with a GABAA receptor agonist.
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Affiliation(s)
- Sahruh Turkmen
- Sundsvalls Research UnitDepartment of Clinical Sciences, Obstetrics and GynaecologyUmeå UniversitySundsvallSweden
| | - Torbjörn Bäckström
- Sundsvalls Research UnitDepartment of Clinical Sciences, Obstetrics and GynaecologyUmeå UniversitySundsvallSweden
| | - Yvonne Kangas Flodin
- Sundsvalls Research UnitDepartment of Clinical Sciences, Obstetrics and GynaecologyUmeå UniversitySundsvallSweden
| | - Marie Bixo
- Sundsvalls Research UnitDepartment of Clinical Sciences, Obstetrics and GynaecologyUmeå UniversitySundsvallSweden
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Quinney SK, Benjamin T, Zheng X, Patil AS. Characterization of Maternal and Fetal CYP3A-Mediated Progesterone Metabolism. Fetal Pediatr Pathol 2017; 36:400-411. [PMID: 28949811 PMCID: PMC5704987 DOI: 10.1080/15513815.2017.1354411] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Progesterone is critical for maintaining pregnancy and onset of labor. We evaluated CYP450-mediated progesterone meta-bolism, specifically the contribution of CYP3A isoforms. MATERIALS AND METHODS In vitro progesterone metabolism was characterized in human liver microsomes (HLMs) with and without selective cytochrome P450 inhibitors and in recombinant CYP3A4, CYP3A5, and CYP3A7. 6β-hydroxyprogesterone (6β-OHP) and 16α-hydroxyprogesterone (16α-OHP) metabolites were quantified by HPLC/UV and fit to the Michaelis-Menten equation to determine Km and Vmax. The effect of CYP3A5 expression on progesterone clearance was determined by in vitro in vivo extrapolation. RESULTS Ketoconazole inhibited formation of both 6β-OHP and 16α-OHP more than 95%. 6β-OHP and 16α-OHP were both produced by CYP3A4 (2.3 and 1.3 µL/min/pmol, respectively) to a greater extent than by CYP3A5 (0.09 and 0.003 µL/min/pmol) and CYP3A7 (0.004 and 0.003 µL/min/pmol). CONCLUSIONS Maternal clearance of progesterone by hepatic CYP450's is driven primarily by CYP3A4, with limited contributions from CYP3A5 and CYP3A7.
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Affiliation(s)
- Sara K Quinney
- a Department of Obstetrics and Gynecology , Indiana University , Indaianpolis , IN , USA
| | - Tara Benjamin
- b Center for Personalized Obstetric Medicine at Valley Perinatal Services , Pheonix , AZ , USA
| | - Xiaomei Zheng
- a Department of Obstetrics and Gynecology , Indiana University , Indaianpolis , IN , USA
| | - Avinash S Patil
- b Center for Personalized Obstetric Medicine at Valley Perinatal Services , Pheonix , AZ , USA
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4
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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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Pregnancy without progesterone in horses defines a second endogenous biopotent progesterone receptor agonist, 5α-dihydroprogesterone. Proc Natl Acad Sci U S A 2014; 111:3365-70. [PMID: 24550466 DOI: 10.1073/pnas.1318163111] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
One of the most widely accepted axioms of mammalian reproductive biology is that pregnancy requires the (sole) support of progesterone, acting in large measure through nuclear progesterone receptors (PRs) in uterine and cervical tissues, without which pregnancy cannot be established or maintained. However, mares lack detectable progesterone in the latter half of pregnancy. Instead of progesterone, several (mainly 5α-reduced) pregnanes are elevated and have long been speculated to provide progestational support in lieu of progesterone itself. To the authors' knowledge, evidence for the bioactivity of a second potent endogenously synthesized pregnane able to support pregnancy in the absence of progesterone has never before been reported. The 5α-reduced progesterone metabolite dihydroprogesterone (DHP) was shown in vivo to stimulate endometrial growth and progesterone-dependent gene expression in the horse at subphysiological concentrations and to maintain equine pregnancy in the absence of luteal progesterone in the third and fourth weeks postbreeding. Results of in vitro studies indicate that DHP is an equally potent and efficacious endogenous progestin in the horse but that the PR evolved with increased agonistic potency for DHP at the expense of potency toward progesterone based on comparisons with human PR responses. Sequence analysis and available literature indicate that the enzyme responsible for DHP synthesis, 5α-reductase type 1, also adapted primarily to metabolize progesterone and thereby to serve diverse roles in the physiology of pregnancy in mammals. Our confirmation that endogenously synthesized DHP is a biopotent progestin in the horse ends decades of speculation, explaining how equine pregnancies survive without measurable circulating progesterone in the last 4 to 5 mo of gestation.
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De Bonis M, Torricelli M, Severi FM, Luisi S, De Leo V, Petraglia F. Neuroendocrine aspects of placenta and pregnancy. Gynecol Endocrinol 2012; 28 Suppl 1:22-6. [PMID: 22394300 DOI: 10.3109/09513590.2012.651933] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Placenta plays a central role in the regulation of physiological mechanisms of pregnancy, and in particular is the organ of communication between mother and fetus. This action is also related to its ability to produce hormones, growth factors and cytokines during the progression of pregnancy, and in response to stimuli such as stress and inflammation/infection. In the last years the understanding of the physiological and pathological functions of human placenta revealed the hypersecretion of hormones in presence of gestational diseases and raised the question whether this mechanism is cause of disorders of pregnancy, or part of an adaptive response of placenta to resolve adverse conditions. However, there are evidences indicating that changes of placental hormone secretion may have clinical usefulness, since they are measurable in biological fluids, and may be used as predictive markers or prognostic tools. Of particular interest is the role of corticotropin releasing hormone, urocortins and activins in the maintaining physiological pregnancy and in the pathogenesis of diseases (preterm birth and preeclampsia).
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Affiliation(s)
- Maria De Bonis
- Chair of Obstetrics and Gynecology, Department of Pediatrics, Obstetrics and Reproductive Medicine, University of Siena, Siena, Italy
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Abstract
The complex mechanisms controlling human parturition involves mother, fetus, and placenta, and stress is a key element activating a series of physiological adaptive responses. Preterm birth is a clinical syndrome that shares several characteristics with term birth. A major role for the neuroendocrine mechanisms has been proposed, and placenta/membranes are sources for neurohormones and peptides. Oxytocin (OT) is the neurohormone whose major target is uterine contractility and placenta represents a novel source that contributes to the mechanisms of parturition. The CRH/urocortin (Ucn) family is another important neuroendocrine pathway involved in term and preterm birth. The CRH/Ucn family consists of four ligands: CRH, Ucn, Ucn2, and Ucn3. These peptides have a pleyotropic function and are expressed by human placenta and fetal membranes. Uterine contractility, blood vessel tone, and immune function are influenced by CRH/Ucns during pregnancy and undergo major changes at parturition. Among the others, neurohormones, relaxin, parathyroid hormone-related protein, opioids, neurosteroids, and monoamines are expressed and secreted from placental tissues at parturition. Preterm birth is the consequence of a premature and sustained activation of endocrine and immune responses. A preterm birth evidence for a premature activation of OT secretion as well as increased maternal plasma CRH levels suggests a pathogenic role of these neurohormones. A decrease of maternal serum CRH-binding protein is a concurrent event. At midgestation, placental hypersecretion of CRH or Ucn has been proposed as a predictive marker of subsequent preterm delivery. While placenta represents the major source for CRH, fetus abundantly secretes Ucn and adrenal dehydroepiandrosterone in women with preterm birth. The relevant role of neuroendocrine mechanisms in preterm birth is sustained by basic and clinic implications.
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Affiliation(s)
- Felice Petraglia
- University of Siena, Policlinico, Division of Obstetrics and Gynecology, Department of Pediatrics, Obstetrics, and Reproductive Medicine, Viale Bracci, 53100 Siena, Italy.
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Hill M, Pařízek A, Kancheva R, Jirásek JE. Reduced progesterone metabolites in human late pregnancy. Physiol Res 2010; 60:225-41. [PMID: 21114373 DOI: 10.33549/physiolres.932077] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this review, we focused on the intersection between steroid metabolomics, obstetrics and steroid neurophysiology to give a comprehensive insight into the role of sex hormones and neuroactive steroids (NAS) in the mechanism controlling pregnancy sustaining. The data in the literature including our studies show that there is a complex mechanism providing synthesis of either pregnancy sustaining or parturition provoking steroids. This mechanism includes the boosting placental synthesis of CRH with approaching parturition inducing the excessive synthesis of 3beta-hydroxy-5-ene steroid sulfates serving primarily as precursors for placental synthesis of progestogens, estrogens and NAS. The distribution and changing activities of placental oxidoreductases are responsible for the activation or inactivation of the aforementioned steroids, which is compartment-specific (maternal and fetal compartments) and dependent on gestational age, with a tendency to shift the production from the pregnancy-sustaining steroids to the parturition provoking ones with an increasing gestational age. The fetal and maternal livers catabolize part of the bioactive steroids and also convert some precursors to bioactive steroids. Besides the progesterone, a variety of its 5alpha/beta-reduced metabolites may significantly influence the maintenance of human pregnancy, provide protection against excitotoxicity following acute hypoxic stress, and might also affect the pain perception in mother and fetus.
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Affiliation(s)
- M Hill
- Department of Obstetrics and Gynecology of the First Faculty of Medicine and General Teaching Hospital, Prague, Czech Republic.
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Affiliation(s)
- Sam Mesiano
- Departments of Reproductive Biology and Obstetrics & Gynecology, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Yuguang Wang
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Errol R. Norwitz
- Department of Obstetrics, Gynecology & Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA
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Hill M, Pařízek A, Velíková M, Kubátová J, Kancheva R, Dušková M, Šimůnková K, Klímková M, Pašková A, Žižka Z, Jirásek JE, Jirkovská M, Stárka L. The distribution of placental oxidoreductase isoforms provides different milieus of steroids influencing pregnancy in the maternal and fetal compartment. Horm Mol Biol Clin Investig 2010; 4:581-600. [DOI: 10.1515/hmbci.2010.077] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 11/24/2010] [Indexed: 12/27/2022]
Abstract
AbstractUsing information based on the steroid metabolome in maternal and fetal body fluids, we attempted to ascertain whether there is a common mechanism, which is based on the placental distribution of various isoforms of 17β-hydroxysteroid dehydrogenases and aldo-keto reductases. This system simultaneously provides a higher proportion of active progestogens in fetal circulation and a higher proportion of active estrogens and GABAergic steroids in the maternal compartment. The data obtained using gas chromatography-mass spectrometry completely support the aforementioned hypothesis. We confirmed a common trend to higher ratios of steroids with hydroxy-groups in the 3α-, 17β-, and 20α-positions to the corresponding 3-oxo-, 17-oxo-, and 20-oxo-metabolites, respectively, in the maternal blood when compared with the fetal circulation, and the same tendency was obvious in the 3α-hydroxy/3β-hydroxy steroid ratios. A decreasing trend was observed in the ratios of active estrogens and neuro-inhibitory steroids to their inactive counterparts in fetal and maternal body fluids. This was probably associated with a limited capacity of placental oxidoreductases in the converting of estrone to estradiol during the transplacental passage. Although we observed a decreasing trend in pregnancy-sustaining steroids with increasing gestational age, we recorded rising levels of estradiol and particularly of estriol, regardless of the limited capacity of placental oxidoreductases. Besides the estradiol, which is generally known as an active estrogen, estriol may be of importance for the termination of pregnancy with respect to its excessive concentrations near term which allows its binding to estrogen receptors.
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Abstract
Almost 80 years ago George Corner and colleagues provided the first evidence that progesterone maintains pregnancy and that it does so, at least in part, by promoting myometrial relaxation. In the 1950s, Arpad Csapo proposed the “progesterone block hypothesis”, which posits that progesterone maintains pregnancy by promoting myometrial relaxation and that its withdrawal initiates a cascade of hormonal interactions that transforms the myometrium to a highly contractile state leading to the onset of labour. Csapo later proposed that contractility of the pregnant myometrium is determined by the balance between relaxation induced by progesterone and contraction induced by a cohort of signals including oestrogens, uterine distention and stimulatory uterotonins such as prostaglandins (PGs) and oxytocin (OT). According to this “seesaw” hypothesis, progesterone promotes myometrial relaxation by directly inducing relaxation and/or by inhibiting the production of, or myometrial responsiveness to, stimulatory uterotonins. These landmark concepts, though derived from studies of experimental animals, form the foundation for current understanding of progesterone's role in the physiology of human pregnancy. Remarkable progress has been made over the last 20–30 years in understanding the signal transduction pathways through which steroid hormones affect target cells. This knowledge has broadened the scope of Csapo's original paradigms and we are now beginning to unravel the specific signaling pathways and molecular interactions by which progesterone affects human myometrium and how its actions are controlled at the functional level. This is important for the development of progestin-based therapeutics for the prevention or suppression of preterm labour and preterm birth. Here we review recent progress in understanding the mechanisms by which progesterone sustains pregnancy and in particular how it promotes myometrial relaxation, how its relaxatory actions are nullified at parturition, and the hormonal interactions that induce progesterone withdrawal to determine the timing of human birth.
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Mesiano S, Welsh TN. Steroid hormone control of myometrial contractility and parturition. Semin Cell Dev Biol 2007; 18:321-31. [PMID: 17613262 DOI: 10.1016/j.semcdb.2007.05.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 05/03/2007] [Indexed: 01/04/2023]
Abstract
The precise temporal control of uterine contractility is essential for the success of pregnancy. For most of pregnancy, progesterone acting through genomic and non-genomic mechanisms promotes myometrial relaxation. At parturition the relaxatory actions of progesterone are nullified and the combined stimulatory actions of estrogens and other factors such as myometrial distention and immune/inflammatory cytokines, transform the myometrium to a highly contractile and excitable state leading to labor and delivery. This review addresses current understanding of how progesterone and estrogens affect the contractility of the pregnancy myometrium and how their actions are coordinated and controlled as part of the parturition cascade.
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Affiliation(s)
- Sam Mesiano
- Department of Reproductive Biology, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-5034, United States.
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Domali E, Molyvdas PA, Messinis IE. In vitro responsiveness of human post-menopausal myometrium to endothelin-1 and ovarian steroids. J Endocrinol Invest 2005; 28:485-93. [PMID: 16117188 DOI: 10.1007/bf03347235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
It has been shown in vitro that endothelin 1 (ET1) differentially affects the human myometrial contractility according to the hormonal profile of women. Our purpose was to test the hypothesis that ovarian steroids influence the ET1 induced myometrial contractility. We performed three types of experiments. Myometrial tissues were exposed to 17beta-oestradiol (E), progesterone (P), E plus P (E+P) in concentrations 10(-10)M, 10(-8)M, 10(-7)M, 10(-6)M and 10(-4)M (Type I), ET1 in concentrations 10(-10)M, 10(-9)M, 10(-8)M, 10(-7)M and 10(-6)M (Type II) and E+ET1, P+ET1 and E+P+ET1 in concentrations ranging from 10(-10)M to 10(-6)M (Type III). Tissue exposure to E, P and E+P did not significantly alter the pattern of spontaneous myometrial motility. ET1 (10(-6)M) induced a sustained long-lasting contraction, the initial part of which lasted 34 +/- 4 min, elevating the initial baseline by 190 +/- 20%. This was followed by ripples of gradually increasing amplitude with no regular contractions up to the end of the period of observation (120 min). Addition of P or E+P to ET1 markedly restricted (p<0.05) the elevation of initial baseline (P+ET1: 68 +/- 8%, P+E+ET1: 67 +/- 8%), and significantly shortened (p<0.01) the duration of the alterations (P+ET1: 21 +/- 3 min, P+E+ET1: 26 +/- 3 min). These results demonstrate the lack of any significant effect of E and P or their combinations on the pattern of spontaneous myometrial motility in post-menopausal women. However, P alone or in combination with E exerted an inhibitory action on ET1 -induced contractility on human post-menopausal myometrium. The physiological significance of these findings remains to be clarified.
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Affiliation(s)
- E Domali
- Department of Physiology, Medical School, Medical School, University of Thessalia, Larissa, Greece
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Ousey JC, Houghton E, Grainger L, Rossdale PD, Fowden AL. Progestagen profiles during the last trimester of gestation in Thoroughbred mares with normal or compromised pregnancies. Theriogenology 2005; 63:1844-56. [PMID: 15823343 DOI: 10.1016/j.theriogenology.2004.08.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2003] [Revised: 06/10/2004] [Accepted: 08/18/2004] [Indexed: 11/21/2022]
Abstract
Progesterone (P4), pregnenolone (P5) and their metabolites are present in maternal plasma in pregnant mares. It is believed that one of these progestagens may maintain myometrial quiescence. The aims of this study were to identify specific progestagens in pregnant mares' plasma and determine whether these differed between mares with healthy or compromised pregnancies. Jugular blood samples were collected between 243 and 351 days gestation from 19 healthy Thoroughbred mares and 14 mares with placental pathology, including placentitis, and other clinical problems (uterine torsion/rupture, colic, laminitis). Ten progestagens were identified using gas chromatography-mass spectrometry, of which seven increased significantly with gestational age in healthy mares while P4 was undetectable. Mares with placentitis had increased concentrations of either P5 and/or P4 and several metabolites (5alpha-DHP, P5betabeta, betabeta-diol, betaalpha-diol, 20alpha-5P) suggesting increased fetal production of P5 and/or P4 and increased metabolism in the utero-placental tissues in response to chronic stress. Mares with other placental pathology had raised P4 concentrations while 5alpha-DHP and 3beta-5P were low possibly due to reduced placental function. In mares with problems unrelated to the placenta, most progestagens were substantially lower than control values. Although progestagen profiles differed between normal and abnormal pregnancies, no clear link was demonstrated between maternal plasma concentrations of P4, 5alpha-DHP or any other progestagen and the maintenance of pregnancy.
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Affiliation(s)
- Jennifer C Ousey
- Department of Physiology, University of Cambridge, Downing Street, Cambridge, CB23EG, UK.
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15
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Functional effects of 17alpha-hydroxyprogesterone caproate (17P) on human myometrial contractility in vitro. Reprod Biol Endocrinol 2004; 2:80. [PMID: 15585068 PMCID: PMC539291 DOI: 10.1186/1477-7827-2-80] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Accepted: 12/07/2004] [Indexed: 11/26/2022] Open
Abstract
Background 17alpha-hydroxyprogesterone caproate (17P) administration reportedly improves outcome for women with a previous spontaneous preterm delivery. This study, using in vitro strips of human uterine smooth muscle, aimed to investigate the direct non-genomic effects of 17P on spontaneous and induced contractions in tissues obtained during pregnancy, and in the non-pregnant state. Methods Biopsies of human myometrium were obtained at elective cesarean section, and from hysterectomy specimens, and dissected strips suspended for isometric recordings. The effects of 17P (1 nmol/L -10 micro mol/L) on spontaneous and agonist-induced (oxytocin 0.5 nmol/L for pregnant, phenylephrine 10 μmol/L for non-pregnant) contractions were measured. Integrals of contractile activity, including the mean maximal inhibition values (MMI) observed at the maximal concentration, were compared with those from simultaneously run control strips. Results There was no significant direct effect exerted by 17P on pregnant or non-pregnant human myometrial contractility. The MMI ± SEM for spontaneous contractions in pregnant myometrium was 4.9% ± 7.2 (n = 6; P = 0.309) and for oxytocin-induced contractions was 2.2% ± 1.3 (n = 6; P = 0.128). For non-pregnant myometrium, the MMI ± SEM for spontaneous contractions was 8.8% ± 11.0 (n = 6; P = 0.121) and for phenylephrine induced contractions was -7.9% ± 6.5 (n = 6; P = 0.966). Conclusions The putative benefits of 17P for preterm labor prevention are not achieved, even partially, by a direct utero-relaxant effect. These findings outline the possibility that genomic effects of 17P, achieved over long periods of administration, are required for its reported therapeutic benefits.
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Abstract
Dehydroepiandrosterone (DHEA), a 19-carbon precursor of sex steroids, is abundantly produced in the human but not the mouse adrenal. However, mice produce DHEA and DHEA-sulfate (DHEAS) in the fetal brain. DHEA stimulates axonal growth from specific populations of mouse neocortical neurons in vitro, while DHEAS stimulates dendritic growth from those cells. The synthesis of DHEA and sex steroids, but not mouse glucocorticoids and mineralocorticoids, requires P450c17, which catalyzes both 17 alpha-hydroxylase and 17,20-lyase activities. We hypothesized that P450c17-knockout mice would have disordered sex steroid synthesis and disordered brain DHEA production and thus provide phenotypic clues about the functions of DHEA in mouse brain development. We deleted the mouse P450c17 gene in 127/SvJ mice and obtained several lines of mice from two lines of targeted embryonic stem cells. Heterozygotes were phenotypically and reproductively normal, but in all mouse lines, P450c17(-/-) zygotes died by embryonic day 7, prior to gastrulation. The cause of this early lethality is unknown, as there is no known function of fetal steroids at embryonic day 7. Immunocytochemistry identified P450c17 in embryonic endoderm in E7 wild-type and heterozygous embryos, but its function in these cells is unknown. Enzyme assays of wild-type embryos showed a rapid rise in 17-hydroxylase activity between E6 and E7 and the presence of C(17,20)-lyase activity at E7. Treatment of pregnant females with subcutaneous pellets releasing DHEA or 17-OH pregnenolone at a constant rate failed to rescue P450c17(-/-) fetuses. Treatment of normal pregnant females with pellets releasing pregnenolone or progesterone did not cause fetal demise. These data suggest that steroid products of P450c17 have heretofore-unknown essential functions in early embryonic mouse development.
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Affiliation(s)
- Susanna R Bair
- Department of Obstetrics, Gynecology, and Reproductive Sciences, The Center for Reproductive Sciences, and The Metabolic Research Unit, University of California, San Francisco, 94143, USA
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Ousey JC, Forhead AJ, Rossdale PD, Grainger L, Houghton E, Fowden AL. Ontogeny of uteroplacental progestagen production in pregnant mares during the second half of gestation. Biol Reprod 2003; 69:540-8. [PMID: 12700198 DOI: 10.1095/biolreprod.102.013292] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In pregnant mares during late gestation, little, if any, progesterone (P4) is found in the maternal circulation. Hence, quiescence of the equine uterus is believed to be maintained by metabolites of pregnenolone and P4 known as progestagens, which are produced by the uteroplacental tissues. However, little is known about the ontogeny, distribution, or actual rates of uteroplacental progestagen production in pregnant mares and their fetuses during the second half of pregnancy. Therefore, the present study measured the rates of uteroplacental uptake and output of eight specific progestagens in chronically catheterized, pregnant pony mares from 180 days to term. No significant uteroplacental uptake of any of the eight individual progestagens was observed from the uterine circulation. In contrast, significant uteroplacental uptake was observed for five of the eight individual progestagens from the umbilical circulation, and the uptakes increased toward term. The major uteroplacental progestagen outputs were 5 alpha-pregnane-3,20-dione (5 alphaDHP) and 20 alpha-hydroxy-5 alpha-pregnan-3-one (20 alpha 5P). These were released into both the umbilical and uterine circulations at rates that increased toward term. The majority of the total uteroplacental 20 alpha 5P output was distributed into the uterine circulation at all gestational ages studied. In contrast, distribution of the total uteroplacental 5 alphaDHP output switched from preferential delivery into the uterine circulation before 220 days of gestation to release predominantly into the umbilical circulation after 260 days. These findings demonstrate that uteroplacental progestagen production changes during the second half of gestation, which may have important implications for the maintenance of pregnancy and the onset of labor in the mare.
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Affiliation(s)
- J C Ousey
- Department of Physiology, University of Cambridge, Cambridge, CB2 3EG, United Kingdom
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Chavatte P, Holtan D, Ousey JC, Rossdale PD. Biosynthesis and possible biological roles of progestagens during equine pregnancy and in the newborn foal. Equine Vet J 1997:89-95. [PMID: 9355808 DOI: 10.1111/j.2042-3306.1997.tb05084.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Major progress on the endocrinology of the pregnant mare has been possible thanks to the catheterised equine fetal preparation developed by Marian Silver. In particular, these preparations led to the identification of the source of progestagens within the feto-placental unit and provided the impetus for further work on their biosynthesis and biological activities. The biosynthesis of the progestagens involves close interaction between the fetus, the endometrium and the placenta, and gives rise to some fundamental biochemical questions. The biological role of the progestagens is also discussed: these compounds may have progestagenic activities but may also play a role in the onset of parturition.
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Affiliation(s)
- P Chavatte
- 3 La Cour Verte, Maincourt, Dampierre sur Yvette, France
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Rezapour M, Hongpaisan J, Fu X, Bäckström T, Roomans GM, Ulmsten U. Effects of progesterone and oxytocin on intracellular elemental composition of term human myometrium in vitro. Eur J Obstet Gynecol Reprod Biol 1996; 68:191-7. [PMID: 8886706 DOI: 10.1016/0301-2115(96)02503-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To study the effects of progesterone and oxytocin on contractile activity related to the intracellular elemental composition of human pregnant myometrium. STUDY DESIGN Myometrial strips were mounted in tissue baths and superfused with plain buffer, oxytocin or progesterone. Progesterone was initially added to the tissue bath or at the onset of spontaneous contraction of the strips. The myometrial contractile activities were recorded isometrically and the results were analyzed by a specific computer program. The effects of oxytocin and progesterone on the intracellular elemental composition were studied by X-ray microanalysis in an electron microscope. RESULTS The contractile activity in terms of frequency and tonus of the muscle strips was increased by oxytocin and progesterone. This increase was more pronounced if progesterone was added to the bath at the start of the experiment. After 120 min of incubation with oxytocin and progesterone the total intracellular concentration of calcium was significantly higher (P < 0.0001 and P < 0.002, respectively) compared to buffer. CONCLUSIONS (i) Oxytocin increases total intracellular calcium concentration concomitant with an increase in uterine contractile activity. (ii) Progesterone increases the myometrial tone and frequency of contractions, simultaneously with an increase in total intracellular calcium.
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Affiliation(s)
- M Rezapour
- Department of Obstetrics and Gynecology, University of Uppsala, Academic Hospital, Sweden.
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