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Marchetti C, Grisolia-Romero M, Priotto M, Faya M, Gobello C. Clinical, Ovulatory and Histological Effect of a Postnatal Testosterone Treatment in Female Dogs. Animals (Basel) 2024; 14:1049. [PMID: 38612288 PMCID: PMC11011087 DOI: 10.3390/ani14071049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
It has been described in some female mammalian species that postnatal androgenization causes reproductive structural and functional abnormalities. The objective of this study was to describe the clinical, ovulatory and genital effects of postnatal androgens in female dogs. Ten newborn female crossbred puppies were randomly assigned to: testosterone enanthate 18 mg/100 g sc (TE; n = 5) or placebo sc (PL; n = 5). The puppies were physically followed up until puberty when ovulation was tested by serum progesterone. Then, ovariohysterectomies were performed, and genital tracts were grossly and histomorphometrically examined. At puberty, all the females had normal estrous behavior and ovulated without age and body weight differences. All TE puppies presented mild clitoris enlargement. Gross and microscopical ovarian examination did not reveal differences. Conversely, the endometrial area occupied by uterine glands as well as the height of the glandular and luminal epithelium were higher in the TE than in the PL group (<0.01). The height of the endometrium and myometrial thickness did not differ between groups. It was concluded that a supraphysiological postnatal dose of testosterone did not affect ovulatory capacity, nor did it provoke gonadal histological alterations, although it caused an increased area of endometrial glands and a higher uterine epithelium.
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Affiliation(s)
- Cynthia Marchetti
- Research Institute of Natural Resources & Sustainability José Sanchez Labrador S.J., Catholic University of Córdoba, Córdoba 5000, Argentina; (C.M.); (M.G.-R.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires 2290, Argentina
| | - Mariela Grisolia-Romero
- Research Institute of Natural Resources & Sustainability José Sanchez Labrador S.J., Catholic University of Córdoba, Córdoba 5000, Argentina; (C.M.); (M.G.-R.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires 2290, Argentina
| | - Marcelo Priotto
- Small Animal Clinics, Faculty of Agricultural Sciences, Catholic University of Córdoba, Córdoba 5000, Argentina;
| | - Marcela Faya
- Research Institute of Natural Resources & Sustainability José Sanchez Labrador S.J., Catholic University of Córdoba, Córdoba 5000, Argentina; (C.M.); (M.G.-R.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires 2290, Argentina
| | - Cristina Gobello
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires 2290, Argentina
- Center of Reproductive Physiology, Faculty of Veterinary Sciences, National University of La Plata, La Plata 1900, Argentina
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2
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Amodei R, Jonker SS, Smallman M, Whitler W, Estill CT, Roselli CE. Effect of Fetal Pituitary-Testes Suppression on Brain Sexual Differentiation and Reproductive Function in Male Sheep. Endocrinology 2023; 164:bqad129. [PMID: 37610243 PMCID: PMC10484288 DOI: 10.1210/endocr/bqad129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/31/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
We previously demonstrated that treating fetal lambs on gestational day 62 with the long-acting gonadotrophin-releasing hormone (GnRH) antagonist degarelix (DG) suppresses pituitary-testicular function during midgestation. The objective of this study was to investigate whether impaired gonadotrophic drive during this fetal period has enduring effects on sexual differentiation and reproductive function in adult male sheep. We assessed the effects of prenatal administration of DG, with or without testosterone (T) replacement, on various sexually dimorphic behavioral traits in adult rams, including sexual partner preferences, as well as neuroendocrine responsiveness and testicular function. Our findings revealed that DG treatment had no effect on genital differentiation or somatic growth. There were some indications that DG treatment suppressed juvenile play behavior and adult sexual motivation; however, male-typical sexual differentiation of reproductive behavior, sexual partner preference, and gonadotropin feedback remained unaffected and appeared to be fully masculinized and defeminized. DG-treated rams showed an increased LH response to GnRH stimulation and a decreased T response to human chorionic gonadotropin stimulation, suggesting impaired Leydig cell function and reduced T feedback. Both effects were reversed by cotreatment with T propionate. DG treatment also suppressed the expression of CYP17 messenger RNA, a key enzyme for T biosynthesis. Despite the mild hypogonadism induced by DG treatment, ejaculate volume, sperm motility, and sperm morphology were not affected. In summary, these results suggest that blocking GnRH during midgestation does not have enduring effects on brain sexual differentiation but does negatively affect the testes' capacity to synthesize T.
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Affiliation(s)
- Rebecka Amodei
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Sonnet S Jonker
- Center for Developmental Health, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Mary Smallman
- Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR 97331-4501, USA
| | - William Whitler
- College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4501, USA
| | - Charles T Estill
- Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR 97331-4501, USA
- College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4501, USA
| | - Charles E Roselli
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239-3098, USA
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Screening of Differentially Expressed Genes and miRNAs in Hypothalamus and Pituitary Gland of Sheep under Different Photoperiods. Genes (Basel) 2022; 13:genes13061091. [PMID: 35741853 PMCID: PMC9222358 DOI: 10.3390/genes13061091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 12/05/2022] Open
Abstract
The reproduction of sheep is affected by many factors such as light, nutrition and genetics. The Hypothalamic-pituitary-gonadal (HPG) axis is an important pathway for sheep reproduction, and changes in HPG axis-related gene expression can affect sheep reproduction. In this study, a model of bilateral ovarian removal and estrogen supplementation (OVX + E2) was applied to screen differentially expressed genes and miRNAs under different photoperiods using whole transcriptome sequencing and reveal the regulatory effects of the photoperiod on the upstream tissues of the HPG axis in sheep. Whole transcriptome sequencing was performed in ewe hypothalamus (HYP) and distal pituitary (PD) tissues under short photoperiod 21st day (SP21) and long photoperiod 21st day (LP21). Compared to the short photoperiod, a total of 1813 differential genes (up-regulation 966 and down-regulation 847) and 145 differential miRNAs (up-regulation 73 and down-regulation 72) were identified in the hypothalamus of long photoperiod group. Similarly, 2492 differential genes (up-regulation 1829 and down-regulation 663) and 59 differential miRNAs (up-regulation 49 and down-regulation 10) were identified in the pituitary of long photoperiod group. Subsequently, GO and KEGG enrichment analysis revealed that the differential genes and target genes of differential miRNA were enriched in GnRH, Wnt, ErbB and circadian rhythm pathways associated with reproduction. Combined with sequence complementation and gene expression correlation analysis, several miRNA-mRNA target combinations (e.g., LHB regulated by novel-414) were obtained. Taken together, these results will help to understand the regulatory effect of the photoperiod on the upstream tissues of HPG in sheep.
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He X, Tao L, Zhong Y, Di R, Xia Q, Wang X, Guo X, Gan S, Zhang X, Zhang J, Liu Q, Chu M. Photoperiod induced the pituitary differential regulation of lncRNAs and mRNAs related to reproduction in sheep. PeerJ 2021; 9:e10953. [PMID: 33976954 PMCID: PMC8067910 DOI: 10.7717/peerj.10953] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 01/27/2021] [Indexed: 12/12/2022] Open
Abstract
The pituitary is a vital endocrine organ that regulates animal seasonal reproduction by controlling the synthesis and secretion of the hormone. The change of photoperiod is the key factor affecting the function of the pituitary in animals, but the mechanism is unclear. Here, we studied the transcriptomic variation in pars distalis (PD) of the pituitary between short photoperiod (SP) and long photoperiod (LP) using RNA sequencing based on the OVX+E2 sheep. 346 differentially expressed (DE) lncRNAs and 186 DE-mRNA were found in the PD. Moreover, function annotation analysis indicated that the reproductive hormones and photoperiod response-related pathways including aldosterone synthesis and secretion, insulin secretion, thyroid hormone synthesis, and circadian entrainment were enriched. The interaction analysis of mRNA-lncRNA suggested that MSTRG.240648, MSTRG.85500, MSTRG.32448, and MSTRG.304959 targeted CREB3L1 and DUSP6, which may be involved in the photoperiodic regulation of the PD. These findings provide resources for further study on the seasonal reproductive in ewes.
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Affiliation(s)
- Xiaoyun He
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lin Tao
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yingjie Zhong
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ran Di
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qing Xia
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiangyu Wang
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaofei Guo
- Tianjin Institute of Animal Sciences, Tianjin, China
| | - Shangquan Gan
- Xinjiang Academy of Agricultural and Reclamation Sciences, Xinjiang, China
| | | | - Jinlong Zhang
- Tianjin Institute of Animal Sciences, Tianjin, China
| | - Qiuyue Liu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Mingxing Chu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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Stener-Victorin E, Padmanabhan V, Walters KA, Campbell RE, Benrick A, Giacobini P, Dumesic DA, Abbott DH. Animal Models to Understand the Etiology and Pathophysiology of Polycystic Ovary Syndrome. Endocr Rev 2020; 41:bnaa010. [PMID: 32310267 PMCID: PMC7279705 DOI: 10.1210/endrev/bnaa010] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/14/2020] [Indexed: 12/14/2022]
Abstract
More than 1 out of 10 women worldwide are diagnosed with polycystic ovary syndrome (PCOS), the leading cause of female reproductive and metabolic dysfunction. Despite its high prevalence, PCOS and its accompanying morbidities are likely underdiagnosed, averaging > 2 years and 3 physicians before women are diagnosed. Although it has been intensively researched, the underlying cause(s) of PCOS have yet to be defined. In order to understand PCOS pathophysiology, its developmental origins, and how to predict and prevent PCOS onset, there is an urgent need for safe and effective markers and treatments. In this review, we detail which animal models are more suitable for contributing to our understanding of the etiology and pathophysiology of PCOS. We summarize and highlight advantages and limitations of hormonal or genetic manipulation of animal models, as well as of naturally occurring PCOS-like females.
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Affiliation(s)
| | - Vasantha Padmanabhan
- Departments of Pediatrics, Obstetrics and Gynecology, and Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan
| | - Kirsty A Walters
- Fertility & Research Centre, School of Women’s and Children’s Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Rebecca E Campbell
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Anna Benrick
- Department of Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- School of Health Sciences and Education, University of Skövde, Skövde, Sweden
| | - Paolo Giacobini
- University of Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, F-59000 Lille, France
| | - Daniel A Dumesic
- Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California, California
| | - David H Abbott
- Department of Obstetrics and Gynecology, Wisconsin National Primate Research Center, University of Wisconsin, Madison, Wisconsin
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6
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Lopez JA, Bowdridge EC, McCosh RB, Bedenbaugh MN, Lindo AN, Metzger M, Haller M, Lehman MN, Hileman SM, Goodman RL. Morphological and functional evidence for sexual dimorphism in neurokinin B signalling in the retrochiasmatic area of sheep. J Neuroendocrinol 2020; 32:e12877. [PMID: 32572994 PMCID: PMC7449597 DOI: 10.1111/jne.12877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 11/26/2022]
Abstract
Neurokinin B (NKB) is critical for fertility in humans and stimulates gonadotrophin-releasing hormone/luteinising hormone (LH) secretion in several species, including sheep. There is increasing evidence that the actions of NKB in the retrochiasmatic area (RCh) contribute to the induction of the preovulatory LH surge in sheep. In the present study, we determined whether there are sex differences in the response to RCh administration of senktide, an agonist to the NKB receptor (neurokinin receptor-3 [NK3R]), and in NKB and NK3R expression in the RCh of sheep. To normalise endogenous hormone concentrations, animals were gonadectomised and given implants to mimic the pattern of ovarian steroids seen in the oestrous cycle. In females, senktide microimplants in the RCh produced an increase in LH concentrations that lasted for at least 8 hours after the start of treatment, whereas a much shorter increment (approximately 2 hours) was seen in males. We next collected tissue from gonadectomised lambs 18 hours after the insertion of oestradiol implants that produce an LH surge in female, but not male, sheep for immunohistochemical analysis of NKB and NK3R expression. As expected, there were more NKB-containing neurones in the arcuate nucleus of females than males. Interestingly, there was a similar sexual dimorphism in NK3R-containing neurones in the RCh, NKB-containing close contacts onto these RCh NK3R neurones, and overall NKB-positive fibres in this region. These data demonstrate that there are both functional and morphological sex differences in NKB-NK3R signalling in the RCh and raise the possibility that this dimorphism contributes to the sex-dependent ability of oestradiol to induce an LH surge in female sheep.
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Affiliation(s)
- Justin A Lopez
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Elizabeth C Bowdridge
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Richard B McCosh
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Michelle N Bedenbaugh
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Ashley N Lindo
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Makayla Metzger
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Megan Haller
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Michael N Lehman
- Department of Biological Sciences, Brain Health Research Institute, Kent State University, Kent, OH, USA
| | - Stanley M Hileman
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Robert L Goodman
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
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Porter DT, Moore AM, Cobern JA, Padmanabhan V, Goodman RL, Coolen LM, Lehman MN. Prenatal Testosterone Exposure Alters GABAergic Synaptic Inputs to GnRH and KNDy Neurons in a Sheep Model of Polycystic Ovarian Syndrome. Endocrinology 2019; 160:2529-2542. [PMID: 31415088 PMCID: PMC6779074 DOI: 10.1210/en.2019-00137] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/05/2019] [Indexed: 12/29/2022]
Abstract
Prenatal testosterone (T)-treated female sheep display reproductive deficits similar to women with polycystic ovarian syndrome (PCOS), including an increase in LH pulse frequency due to actions of the central GnRH pulse generator. In this study, we used multiple-label immunocytochemistry to investigate the possibility of changes in the γ-aminobutyric acid (GABA) neurotransmitter system at two key components of the GnRH pulse generator in prenatal T-treated sheep: kisspeptin/neurokinin B/dynorphin (KNDy) neurons of the arcuate nucleus, and GnRH neurons in the preoptic area (POA) and mediobasal hypothalamus (MBH). We observed a significant decrease and increase, respectively, in the number of GABAergic synapses onto POA and MBH GnRH neurons in prenatal T-treated ewes; additionally, there was a significant increase in the number of GABAergic inputs onto KNDy neurons. To determine the actions of GABA on GnRH and KNDy neurons, we examined colocalization with the chloride transporters NKCC1 and KCC2, which indicate stimulatory or inhibitory activation of neurons by GABA, respectively. Most GnRH neurons in both POA and MBH colocalized NKCC1 cotransporter whereas none contained the KCC2 cotransporter. Most KNDy neurons colocalized either NKCC1 or KCC2, and 28% of the KNDy population contained NKCC1 alone. Therefore, we suggest that, as in the mouse, GABA in the sheep is stimulatory to GnRH neurons, as well as to a subset of KNDy neurons. Increased numbers of stimulatory GABAergic inputs to both MBH GnRH and KNDy neurons in prenatal T-treated animals may contribute to alterations in steroid feedback control and increased GnRH/LH pulse frequency seen in this animal model of PCOS.
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Affiliation(s)
- Danielle T Porter
- Graduate Program in Neuroscience, Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | - Aleisha M Moore
- Brain Health Research Institute, Kent State University, Kent, Ohio
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Jade A Cobern
- Graduate Program in Neuroscience, Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | | | - Robert L Goodman
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, West Virginia
| | - Lique M Coolen
- Graduate Program in Neuroscience, Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
- Brain Health Research Institute, Kent State University, Kent, Ohio
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Michael N Lehman
- Graduate Program in Neuroscience, Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
- Brain Health Research Institute, Kent State University, Kent, Ohio
- Department of Biological Sciences, Kent State University, Kent, Ohio
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8
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Caton JS, Crouse MS, Reynolds LP, Neville TL, Dahlen CR, Ward AK, Swanson KC. Maternal nutrition and programming of offspring energy requirements. Transl Anim Sci 2019; 3:976-990. [PMID: 32704862 PMCID: PMC7200455 DOI: 10.1093/tas/txy127] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 11/19/2018] [Indexed: 01/18/2023] Open
Affiliation(s)
- Joel S Caton
- Department of Animal Sciences, North Dakota State University, Fargo, ND
| | - Matthew S Crouse
- Department of Animal Sciences, North Dakota State University, Fargo, ND
| | | | - Tammi L Neville
- Department of Animal Sciences, North Dakota State University, Fargo, ND
| | - Carl R Dahlen
- Department of Animal Sciences, North Dakota State University, Fargo, ND
| | - Alison K Ward
- Department of Animal Sciences, North Dakota State University, Fargo, ND
| | - Kendall C Swanson
- Department of Animal Sciences, North Dakota State University, Fargo, ND
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9
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Puttabyatappa M, Cardoso RC, Padmanabhan V. Effect of maternal PCOS and PCOS-like phenotype on the offspring's health. Mol Cell Endocrinol 2016; 435:29-39. [PMID: 26639019 PMCID: PMC4884168 DOI: 10.1016/j.mce.2015.11.030] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/02/2015] [Accepted: 11/24/2015] [Indexed: 12/17/2022]
Abstract
Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder with both reproductive and metabolic abnormalities affecting women of reproductive age. While the exact origin of PCOS is unknown, observations from clinical and animal studies suggest that maternal hyperandrogenism may be a contributing factor. Because women with PCOS manifest hyperandrogenism during pregnancy, changes in the gestational endocrine milieu may play a role in the vertical transmission of this syndrome. This review discusses the potential developmental origins of PCOS, the impact of maternal PCOS on the offspring's health and contributions of the postnatal environment, capitalizing on findings from animal models that exhibit a PCOS-like phenotype. In addition, this review highlights the scarcity of data at early gestational stages in humans and the importance of animal experimentation to better understand the cellular and molecular mechanisms involved in the programming of adult diseases, therefore, helping identify therapeutic targets for preventive and treatment strategies.
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Affiliation(s)
| | - Rodolfo C Cardoso
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
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Roselli CE, Amodei R, Gribbin KP, Corder K, Stormshak F, Estill CT. Excess Testosterone Exposure Alters Hypothalamic-Pituitary-Testicular Axis Dynamics and Gene Expression in Sheep Fetuses. Endocrinology 2016; 157:4234-4245. [PMID: 27673555 PMCID: PMC5086533 DOI: 10.1210/en.2016-1411] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prenatal exposure to excess androgen may result in impaired adult fertility in a variety of mammalian species. However, little is known about what feedback mechanisms regulate gonadotropin secretion during early gestation and how they respond to excess T exposure. The objective of this study was to determine the effect of exogenous exposure to T on key genes that regulate gonadotropin and GnRH secretion in fetal male lambs as compared with female cohorts. We found that biweekly maternal testosterone propionate (100 mg) treatment administered from day 30 to day 58 of gestation acutely decreased (P < .05) serum LH concentrations and reduced the expression of gonadotropin subunit mRNA in both sexes and the levels of GnRH receptor mRNA in males. These results are consistent with enhanced negative feedback at the level of the pituitary and were accompanied by reduced mRNA levels for testicular steroidogenic enzymes, suggesting that Leydig cell function was also suppressed. The expression of kisspeptin 1 mRNA, a key regulator of GnRH neurons, was significantly greater (P < .01) in control females than in males and reduced (P < .001) in females by T exposure, indicating that hypothalamic regulation of gonadotropin secretion was also affected by androgen exposure. Although endocrine homeostasis was reestablished 2 weeks after maternal testosterone propionate treatment ceased, additional differences in the gene expression of GnRH, estrogen receptor-β, and kisspeptin receptor (G protein coupled receptor 54) emerged between the treatment cohorts. These changes suggest the normal trajectory of hypothalamic-pituitary axis development was disrupted, which may, in turn, contribute to negative effects on fertility later in life.
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Affiliation(s)
- Charles E Roselli
- Department of Physiology and Pharmacology (C.E.R., R.A., K.P.G.), Oregon Health and Science University, Portland, Oregon 97239-3098; and Department of Animal and Rangeland Sciences (K.C., F.S., C.T.E.) and College of Veterinary Medicine (C.T.E.), Oregon State University, Corvallis, Oregon 97331-4501
| | - Rebecka Amodei
- Department of Physiology and Pharmacology (C.E.R., R.A., K.P.G.), Oregon Health and Science University, Portland, Oregon 97239-3098; and Department of Animal and Rangeland Sciences (K.C., F.S., C.T.E.) and College of Veterinary Medicine (C.T.E.), Oregon State University, Corvallis, Oregon 97331-4501
| | - Kyle P Gribbin
- Department of Physiology and Pharmacology (C.E.R., R.A., K.P.G.), Oregon Health and Science University, Portland, Oregon 97239-3098; and Department of Animal and Rangeland Sciences (K.C., F.S., C.T.E.) and College of Veterinary Medicine (C.T.E.), Oregon State University, Corvallis, Oregon 97331-4501
| | - Keely Corder
- Department of Physiology and Pharmacology (C.E.R., R.A., K.P.G.), Oregon Health and Science University, Portland, Oregon 97239-3098; and Department of Animal and Rangeland Sciences (K.C., F.S., C.T.E.) and College of Veterinary Medicine (C.T.E.), Oregon State University, Corvallis, Oregon 97331-4501
| | - Fred Stormshak
- Department of Physiology and Pharmacology (C.E.R., R.A., K.P.G.), Oregon Health and Science University, Portland, Oregon 97239-3098; and Department of Animal and Rangeland Sciences (K.C., F.S., C.T.E.) and College of Veterinary Medicine (C.T.E.), Oregon State University, Corvallis, Oregon 97331-4501
| | - Charles T Estill
- Department of Physiology and Pharmacology (C.E.R., R.A., K.P.G.), Oregon Health and Science University, Portland, Oregon 97239-3098; and Department of Animal and Rangeland Sciences (K.C., F.S., C.T.E.) and College of Veterinary Medicine (C.T.E.), Oregon State University, Corvallis, Oregon 97331-4501
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11
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Cao J, Dorris DM, Meitzen J. Neonatal Masculinization Blocks Increased Excitatory Synaptic Input in Female Rat Nucleus Accumbens Core. Endocrinology 2016; 157:3181-96. [PMID: 27285859 PMCID: PMC4967116 DOI: 10.1210/en.2016-1160] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/04/2016] [Indexed: 01/18/2023]
Abstract
Steroid sex hormones and genetic sex regulate the phenotypes of motivated behaviors and relevant disorders. Most studies seeking to elucidate the underlying neuroendocrine mechanisms have focused on how 17β-estradiol modulates the role of dopamine in striatal brain regions, which express membrane-associated estrogen receptors. Dopamine action is an important component of striatal function, but excitatory synaptic neurotransmission has also emerged as a key striatal substrate and target of estradiol action. Here, we focus on excitatory synaptic input onto medium spiny neurons (MSNs) in the striatal region nucleus accumbens core (AcbC). In adult AcbC, miniature excitatory postsynaptic current (mEPSC) frequency is increased in female compared with male MSNs. We tested whether increased mEPSC frequency in female MSNs exists before puberty, whether this increased excitability is due to the absence of estradiol or testosterone during the early developmental critical period, and whether it is accompanied by stable neuron intrinsic membrane properties. We found that mEPSC frequency is increased in female compared with male MSNs before puberty. Increased mEPSC frequency in female MSNs is abolished after neonatal estradiol or testosterone exposure. MSN intrinsic membrane properties did not differ by sex. These data indicate that neonatal masculinization via estradiol and/or testosterone action is sufficient for down-regulating excitatory synaptic input onto MSNs. We conclude that excitatory synaptic input onto AcbC MSNs is organized long before adulthood via steroid sex hormone action, providing new insight into a mechanism by which sex differences in motivated behavior and other AbcC functions may be generated or compromised.
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Affiliation(s)
- Jinyan Cao
- Department of Biological Sciences (J.C., D.M.D., J.M.), North Carolina State University, Raleigh, North Carolina 27695; W.M. Keck Center for Behavioral Biology (J.C., J.M.), North Carolina State University, Raleigh, North Carolina 27695; Center for Human Health and the Environment (J.M.), North Carolina State University, Raleigh, North Carolina 27695; and Comparative Medicine Institute (J.M.), North Carolina State University, Raleigh, North Carolina 27695
| | - David M Dorris
- Department of Biological Sciences (J.C., D.M.D., J.M.), North Carolina State University, Raleigh, North Carolina 27695; W.M. Keck Center for Behavioral Biology (J.C., J.M.), North Carolina State University, Raleigh, North Carolina 27695; Center for Human Health and the Environment (J.M.), North Carolina State University, Raleigh, North Carolina 27695; and Comparative Medicine Institute (J.M.), North Carolina State University, Raleigh, North Carolina 27695
| | - John Meitzen
- Department of Biological Sciences (J.C., D.M.D., J.M.), North Carolina State University, Raleigh, North Carolina 27695; W.M. Keck Center for Behavioral Biology (J.C., J.M.), North Carolina State University, Raleigh, North Carolina 27695; Center for Human Health and the Environment (J.M.), North Carolina State University, Raleigh, North Carolina 27695; and Comparative Medicine Institute (J.M.), North Carolina State University, Raleigh, North Carolina 27695
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12
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Disrupting effect of androgens in postnatal female domestic cats. Anim Reprod Sci 2016; 171:65-71. [DOI: 10.1016/j.anireprosci.2016.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/26/2016] [Accepted: 05/31/2016] [Indexed: 11/17/2022]
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13
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Veiga-Lopez A, Moeller J, Abbott DH, Padmanabhan V. Developmental programming: rescuing disruptions in preovulatory follicle growth and steroidogenesis from prenatal testosterone disruption. J Ovarian Res 2016; 9:39. [PMID: 27357284 PMCID: PMC4928247 DOI: 10.1186/s13048-016-0250-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 06/22/2016] [Indexed: 08/30/2023] Open
Abstract
BACKGROUND Prenatal testosterone (T) excess from days 30-90 of gestation disrupts gonadotropin surge and ovarian follicular dynamics and induces insulin resistance and functional hyperandrogenism in sheep. T treatment from days 60-90 of gestation produces a milder phenotype, albeit with reduced fecundity. Using this milder phenotype, the aim of this study was to understand the relative postnatal contributions of androgen and insulin in mediating the prenatal T induced disruptions in ovarian follicular dynamics. METHODS Four experimental groups were generated: 1) control (vehicle treatment), 2) prenatal T-treated (100 mg i.m. administration of T propionate twice weekly from days 60-90 of gestation), 3) prenatal T plus postnatal anti-androgen treated (daily oral dose of 15 mg/kg/day of flutamide beginning at 8 weeks of age) and 4) prenatal T and postnatal insulin sensitizer-treated (daily oral dose of 8 mg/day rosiglitazone beginning at 8 weeks of age). Follicular response to a controlled ovarian stimulation protocol was tested during their third breeding season. Main outcome measures included the determination of number and size of ovarian follicles and intrafollicular concentrations of steroids. RESULTS At the end of the controlled ovarian stimulation, the number of follicles approaching ovulatory size (≥6 mm) were ~35 % lower in prenatal T-treated (6.5 ± 1.8) compared to controls (9.8 ± 2.0). Postnatal anti-androgen (10.3 ± 1.9), but not insulin sensitizer (5.0 ± 0.9), treatment prevented this decrease. Preovulatory sized follicles in the T group had lower intrafollicular T, androstenedione, and progesterone compared to that of the control group. Intrafollicular steroid disruption was partially reversed solely by postnatal insulin sensitizer treatment. CONCLUSIONS These results demonstrate that the final preovulatory follicular growth and intrafollicular steroid milieu is impaired in prenatal T-treated females. The findings are consistent with the lower fertility rate reported earlier in these females. The finding that final follicle growth was fully rescued by postnatal anti-androgen treatment and intrafollicular steroid milieu partially by insulin sensitizer treatment suggest that both androgenic and insulin pathway disruptions contribute to the compromised follicular phenotype of prenatal T-treated females.
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Affiliation(s)
- A Veiga-Lopez
- Department of Pediatrics, University of Michigan, 7641A Med Sci II, Ann Arbor, MI, 48109-5622, USA.,Department of Animal Science, Michigan State University, East Lansing, MI, 48824, USA
| | - J Moeller
- Department of Pediatrics, University of Michigan, 7641A Med Sci II, Ann Arbor, MI, 48109-5622, USA
| | - D H Abbott
- Department of Obstetrics and Gynecology and Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI, 53715, USA
| | - V Padmanabhan
- Department of Pediatrics, University of Michigan, 7641A Med Sci II, Ann Arbor, MI, 48109-5622, USA.
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14
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Puttabyatappa M, Cardoso RC, Herkimer C, Veiga-Lopez A, Padmanabhan V. Developmental programming: postnatal estradiol modulation of prenatally organized reproductive neuroendocrine function in sheep. Reproduction 2016; 152:139-50. [PMID: 27222598 DOI: 10.1530/rep-16-0065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/23/2016] [Indexed: 12/29/2022]
Abstract
Gestational testosterone (TS) excess, acting via both the androgenic and estrogenic pathways, advances puberty and disrupts the neuroendocrine estradiol (E2) feedback and periovulatory hormonal dynamics in female sheep. These prenatally programmed defects may be subject to postnatal modifications by continued organizational and/or activational effects of steroids. This study investigated (1) the organizational contribution of prenatal estrogen excess and (2) the impact of postnatal exposure to E2 in modulating the effects of prenatal androgen excess (TS and dihydrotestosterone (DHT)) on puberty, neuroendocrine feedback mechanisms, and periovulatory hormonal dynamics in sheep. Pregnant Suffolk sheep were treated with TS, DHT, E2, or E2 plus DHT (ED) from days 30 to 90 of gestation. A subset of the control (C), TS, and DHT female offspring received a constant-release E2 implant postnatally. Findings revealed that (1) prenatal E2-treatment failed to reproduce the neuroendocrine disruptions predicted to be programmed by the estrogenic pathway and (2) prenatal E2D-treatment did not adequately replicate the reproductive neuroendocrine defects induced by prenatal TS excess. More importantly, continuous postnatal E2-treatment, while delaying the onset of puberty and reducing the inhibitory effects of E2 on tonic luteinizing hormone (LH) release, failed to amplify the E2-positive feedback and periovulatory defects induced by prenatal TS-treatment. Our results indicate that disruptions in E2-positive feedback mechanisms and periovulatory gonadotropin secretion induced by prenatal TS-treatment are programmed predominantly during the prenatal life with postnatal exposure to E2 excess not contributing further to these disruptions.
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Affiliation(s)
| | - Rodolfo C Cardoso
- Department of PediatricsUniversity of Michigan, Ann Arbor, Michigan, USA
| | - Carol Herkimer
- Department of PediatricsUniversity of Michigan, Ann Arbor, Michigan, USA
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15
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Roselli CE, Meaker M, Stormshak F, Estill CT. Effects of Long-Term Flutamide Treatment During Development on Sexual Behaviour and Hormone Responsiveness in Rams. J Neuroendocrinol 2016; 28:10.1111/jne.12389. [PMID: 27005749 PMCID: PMC4882258 DOI: 10.1111/jne.12389] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/14/2016] [Accepted: 03/19/2016] [Indexed: 01/06/2023]
Abstract
Testosterone exposure during midgestation differentiates neural circuits controlling sex-specific behaviours and patterns of gonadotrophin secretion in male sheep. Testosterone acts through androgen receptors (AR) and/or after aromatisation to oestradiol and binding to oestrogen receptors. The present study assessed the role of AR activation in male sexual differentiation. We compared rams that were exposed to the AR antagonist flutamide (Flu) throughout the critical period (i.e. days 30-90 of gestation) to control rams and ewes that received no prenatal treatments. The external genitalia of all Flu rams were phenotypically female. Testes were positioned s.c. in the inguinal region of the abdomen, exhibited seasonally impaired androgen secretion and were azospermic. Flu rams displayed male-typical precopulatory and mounting behaviours but could not intromit or ejaculate because they lacked a penis. Flu rams exhibited greater mounting behaviour than control rams and, similar to controls, showed sexual partner preferences for oestrous ewes. Neither control, nor Flu rams responded to oestradiol treatments with displays of female-typical receptive behaviour or LH surge responses, whereas all control ewes responded as expected. The ovine sexually dimorphic nucleus in Flu rams was intermediate in volume between control rams and ewes and significantly different from both. These results indicate that prenatal anti-androgen exposure is not able to block male sexual differentiation in sheep and suggest that compensatory mechanisms intervene to maintain sufficient androgen stimulation during development.
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Affiliation(s)
- Charles E. Roselli
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239-3098
| | - Mary Meaker
- Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR 97331-4501
| | - Fred Stormshak
- Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR 97331-4501
| | - Charles T. Estill
- Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR 97331-4501
- College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4501
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16
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Cernea M, Padmanabhan V, Goodman RL, Coolen LM, Lehman MN. Prenatal Testosterone Treatment Leads to Changes in the Morphology of KNDy Neurons, Their Inputs, and Projections to GnRH Cells in Female Sheep. Endocrinology 2015; 156:3277-91. [PMID: 26061725 PMCID: PMC4541615 DOI: 10.1210/en.2014-1609] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prenatal testosterone (T)-treated ewes display a constellation of reproductive defects that closely mirror those seen in PCOS women, including altered hormonal feedback control of GnRH. Kisspeptin/neurokinin B/dynorphin (KNDy) neurons of the arcuate nucleus (ARC) play a key role in steroid feedback control of GnRH secretion, and prenatal T treatment in sheep causes an imbalance of KNDy peptide expression within the ARC. In the present study, we tested the hypothesis that prenatal T exposure, in addition to altering KNDy peptides, leads to changes in the morphology and synaptic inputs of this population, kisspeptin cells of the preoptic area (POA), and GnRH cells. Prenatal T treatment significantly increased the size of KNDy cell somas, whereas POA kisspeptin, GnRH, agouti-related peptide, and proopiomelanocortin neurons were each unchanged in size. Prenatal T treatment also significantly reduced the total number of synaptic inputs onto KNDy neurons and POA kisspeptin neurons; for KNDy neurons, the decrease was partly due to a decrease in KNDy-KNDy synapses, whereas KNDy inputs to POA kisspeptin cells were unaltered. Finally, prenatal T reduced the total number of inputs to GnRH cells in both the POA and medial basal hypothalamus, and this change was in part due to a decreased number of inputs from KNDy neurons. The hypertrophy of KNDy cells in prenatal T sheep resembles that seen in ARC kisspeptin cells of postmenopausal women, and together with changes in their synaptic inputs and projections to GnRH neurons, may contribute to defects in steroidal control of GnRH observed in this animal model.
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Affiliation(s)
- Maria Cernea
- Department of Neurobiology and Anatomical Sciences (M.C., L.M.C., M.N.L.), The University of Mississippi Medical Center, Jackson, Mississippi 39232; Department of Obstetrics and Gynecology, Pediatrics, and Reproductive Sciences Program (V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Physiology and Pharmacology (R.L.G.), West Virginia University, Morgantown, West Virginia 26506
| | - Vasantha Padmanabhan
- Department of Neurobiology and Anatomical Sciences (M.C., L.M.C., M.N.L.), The University of Mississippi Medical Center, Jackson, Mississippi 39232; Department of Obstetrics and Gynecology, Pediatrics, and Reproductive Sciences Program (V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Physiology and Pharmacology (R.L.G.), West Virginia University, Morgantown, West Virginia 26506
| | - Robert L Goodman
- Department of Neurobiology and Anatomical Sciences (M.C., L.M.C., M.N.L.), The University of Mississippi Medical Center, Jackson, Mississippi 39232; Department of Obstetrics and Gynecology, Pediatrics, and Reproductive Sciences Program (V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Physiology and Pharmacology (R.L.G.), West Virginia University, Morgantown, West Virginia 26506
| | - Lique M Coolen
- Department of Neurobiology and Anatomical Sciences (M.C., L.M.C., M.N.L.), The University of Mississippi Medical Center, Jackson, Mississippi 39232; Department of Obstetrics and Gynecology, Pediatrics, and Reproductive Sciences Program (V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Physiology and Pharmacology (R.L.G.), West Virginia University, Morgantown, West Virginia 26506
| | - Michael N Lehman
- Department of Neurobiology and Anatomical Sciences (M.C., L.M.C., M.N.L.), The University of Mississippi Medical Center, Jackson, Mississippi 39232; Department of Obstetrics and Gynecology, Pediatrics, and Reproductive Sciences Program (V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Physiology and Pharmacology (R.L.G.), West Virginia University, Morgantown, West Virginia 26506
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17
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Carranza A, Faya M, Fernandez P, Barbeito C, Gobello C. Histologic effect of a postnatal slow-release GnRH agonist on feline gonads. Theriogenology 2015; 83:1368-72. [DOI: 10.1016/j.theriogenology.2015.01.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 01/24/2015] [Accepted: 01/26/2015] [Indexed: 11/29/2022]
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18
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Brown ECZ, Steadman CJ, Lee TM, Padmanabhan V, Lehman MN, Coolen LM. Sex differences and effects of prenatal exposure to excess testosterone on ventral tegmental area dopamine neurons in adult sheep. Eur J Neurosci 2015; 41:1157-66. [PMID: 25784297 DOI: 10.1111/ejn.12871] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/19/2015] [Accepted: 02/10/2015] [Indexed: 10/23/2022]
Abstract
Prenatal testosterone (T) excess in sheep results in a wide array of reproductive neuroendocrine deficits and alterations in motivated behavior. The ventral tegmental area (VTA) plays a critical role in reward and motivated behaviors and is hypothesised to be targeted by prenatal T. Here we report a sex difference in the number VTA dopamine cells in the adult sheep, with higher numbers of tyrosine hydroxylase (TH)-immunoreactive (-ir) cells in males than females. Moreover, prenatal exposure to excess T during either gestational days 30-90 or 60-90 resulted in increased numbers of VTA TH-ir cells in adult ewes compared to control females. Stereological analysis confirmed significantly greater numbers of neurons in the VTA of males and prenatal T-treated ewes, which was primarily accounted for by greater numbers of TH-ir cells. In addition, immunoreactivity for TH in the cells was denser in males and prenatal T-treated females, suggesting that sex differences and prenatal exposure to excess T affects both numbers of cells expressing TH and the protein levels within dopamine cells. Sex differences were also noted in numbers of TH-ir cells in the substantia nigra, with more cells in males than females. However, prenatal exposure to excess T did not affect numbers of TH-ir cells in the substantia nigra, suggesting that this sex difference is organised independently of prenatal actions of T. Together, these results demonstrate sex differences in the sheep VTA dopamine system which are mimicked by prenatal treatment with excess T.
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Affiliation(s)
- Erinna C Z Brown
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON, N6A 5C1, Canada
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19
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Ahn T, Fergani C, Coolen LM, Padmanabhan V, Lehman MN. Prenatal testosterone excess decreases neurokinin 3 receptor immunoreactivity within the arcuate nucleus KNDy cell population. J Neuroendocrinol 2015; 27:100-10. [PMID: 25496429 PMCID: PMC4412353 DOI: 10.1111/jne.12244] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 11/11/2014] [Accepted: 12/05/2014] [Indexed: 11/29/2022]
Abstract
Prenatal exposure of the female ovine foetus to excess testosterone leads to neuroendocrine disruptions in adulthood, as demonstrated by defects in responsiveness with respect to the ability of gonadal steroids to regulate gonadotrophin-releasing hormone (GnRH) secretion. In the ewe, neurones of the arcuate nucleus (ARC), which co-expresses kisspeptin, neurokinin B (NKB) and dynorphin (termed KNDy cells), play a key role in steroid feedback control of GnRH and show altered peptide expression after prenatal testosterone treatment. KNDy cells also co-localise NKB receptors (NK3R), and it has been proposed that NKB may act as an autoregulatory transmitter in KNDy cells where it participates in the mechanisms underlying steroid negative-feedback. In addition, recent evidence suggests that NKB/NK3R signalling may be involved in the positive-feedback actions of oestradiol leading to the GnRH/luteinising hormone (LH) surge in the ewe. Thus, we hypothesise that decreased expression of NK3R in KNDy cells may be present in the brains of prenatal testosterone-treated animals, potentially contributing to reproductive defects. Using single- and dual-label immunohistochemistry we found NK3R-positive cells in diverse areas of the hypothalamus; however, after prenatal testosterone treatment, decreased numbers of NK3R immunoreactive (-IR) cells were seen only in the ARC. Moreover, dual-label confocal analyses revealed a significant decrease in the percentage of KNDy cells (using kisspeptin as a marker) that co-localised NK3R. To investigate how NKB ultimately affects GnRH secretion in the ewe, we examined GnRH neurones in the preoptic area (POA) and mediobasal hypothalamus (MBH) for the presence of NK3R. Although, consistent with earlier findings, we found no instances of NK3R co-localisation in GnRH neurones in either the POA or MBH; in addition, > 70% GnRH neurones in both areas were contacted by NK3R-IR presynaptic terminals suggesting that, in addition to its role at KNDy cell bodies, NKB may regulate GnRH neurones by presynaptic actions. In summary, the finding of decreased NK3R within KNDy cells in prenatal testosterone-treated sheep complements previous observations of decreased NKB and dynorphin in the same population, and may contribute to deficits in the feedback control of GnRH/LH secretion in this animal model.
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Affiliation(s)
- T Ahn
- Department of Anatomy & Cell Biology, The University of Western Ontario, London, Canada; Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada
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20
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Cardoso RC, Puttabyatappa M, Padmanabhan V. Steroidogenic versus Metabolic Programming of Reproductive Neuroendocrine, Ovarian and Metabolic Dysfunctions. Neuroendocrinology 2015; 102:226-37. [PMID: 25832114 PMCID: PMC4591099 DOI: 10.1159/000381830] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 03/21/2015] [Indexed: 12/12/2022]
Abstract
The susceptibility of the reproductive system to early exposure to steroid hormones has become a major concern in our modern societies. Human fetuses are at risk of abnormal programming via exposure to endocrine disrupting chemicals, inadvertent use of contraceptive pills during pregnancy, as well as from excess exposure to steroids due to disease states. Animal models provide an unparalleled resource to understand the developmental origin of diseases. In female sheep, prenatal exposure to testosterone excess results in an array of adult reproductive disorders that recapitulate those seen in women with polycystic ovary syndrome (PCOS), including disrupted neuroendocrine feedback mechanisms, increased pituitary sensitivity to gonadotropin-releasing hormone, luteinizing hormone excess, functional hyperandrogenism, and multifollicular ovarian morphology culminating in early reproductive failure. Prenatal testosterone treatment also leads to fetal growth retardation, insulin resistance, and hypertension. Mounting evidence suggests that developmental exposure to an improper steroidal/metabolic environment may mediate the programming of adult disorders in prenatal testosterone-treated females, and these defects are maintained or amplified by the postnatal sex steroid and metabolic milieu. This review addresses the steroidal and metabolic contributions to the development and maintenance of the PCOS phenotype in the prenatal testosterone-treated sheep model, including the effects of prenatal and postnatal treatment with an androgen antagonist or insulin sensitizer as potential strategies to prevent/ameliorate these dysfunctions. Insights obtained from these intervention strategies on the mechanisms underlying these defects are likely to have translational relevance to human PCOS.
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Affiliation(s)
- Rodolfo C Cardoso
- Department of Pediatrics, University of Michigan, Ann Arbor, Mich., USA
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21
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Matsuda F, Nakatsukasa K, Suetomi Y, Naniwa Y, Ito D, Inoue N, Wakabayashi Y, Okamura H, Maeda KI, Uenoyama Y, Tsukamura H, Ohkura S. The luteinising hormone surge-generating system is functional in male goats as in females: involvement of kisspeptin neurones in the medial preoptic area. J Neuroendocrinol 2015; 27:57-65. [PMID: 25367275 DOI: 10.1111/jne.12235] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 10/28/2014] [Accepted: 10/28/2014] [Indexed: 12/21/2022]
Abstract
A luteinising hormone (LH) surge is fundamental to the induction of ovulation in mammalian females. The administration of a preovulatory level of oestrogen evokes an LH surge in ovariectomised females, whereas the response to oestrogen in castrated males differs among species; namely, the LH surge-generating system is sexually differentiated in some species (e.g. rodents and sheep) but not in others (e.g. primates). In the present study, we aimed to determine whether there is a functional LH surge-generating system in male goats, and whether hypothalamic kisspeptin neurones in male goats are involved in the regulation of surge-like LH secretion. By i.v. infusion of oestradiol (E2; 6 μg/h) for 16 h, a surge-like LH increase occurred in both castrated male and ovariectomised female goats, although the mean peak LH concentration was lower and the mean peak of the LH surge was later in males compared to females. Dual staining with KISS1 in situ hybridisation and c-Fos immunohistochemistry revealed that E2 treatment significantly increased c-Fos expression in the medial preoptic area (mPOA) KISS1 cells in castrated males, as well as ovariectomised females. By contrast, dual-labelled cells were scarcely detected in the arcuate nucleus (ARC) after E2 treatment in both sexes. These data suggest that kisspeptin neurones in the mPOA, but not those in the ARC, are involved in the induction of surge-like LH secretion in both male and female goats. In summary, our data show that the mechanism that initiates the LH surge in response to oestrogen, the mPOA kisspeptin neurones, is functional in male goats. Thus, sexual differentiation of the LH surge-generating system would not be applicable to goats.
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Affiliation(s)
- F Matsuda
- Laboratory of Animal Production Science, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya, Japan
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22
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Gonadal steroid neuromodulation of developing and mature hypothalamic neuronal networks. Curr Opin Neurobiol 2014; 29:96-102. [DOI: 10.1016/j.conb.2014.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 06/05/2014] [Indexed: 11/21/2022]
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23
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Porter KL, Hileman SM, Hardy SL, Nestor CC, Lehman MN, Goodman RL. Neurokinin-3 receptor activation in the retrochiasmatic area is essential for the full pre-ovulatory luteinising hormone surge in ewes. J Neuroendocrinol 2014; 26:776-84. [PMID: 25040132 PMCID: PMC4201879 DOI: 10.1111/jne.12180] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/18/2014] [Accepted: 07/14/2014] [Indexed: 11/30/2022]
Abstract
Neurokinin B (NKB) is essential for human reproduction and has been shown to stimulate luteinising hormone (LH) secretion in several species, including sheep. Ewes express the neurokinin-3 receptor (NK3R) in the retrochiasmatic area (RCh) and there is one report that placement of senktide, an NK3R agonist, therein stimulates LH secretion that resembles an LH surge in ewes. In the present study, we first confirmed that local administration of senktide to the RCh produced a surge-like increase in LH secretion, and then tested the effects of this agonist in two other areas implicated in the control of LH secretion and where NK3R is found in high abundance: the preoptic area (POA) and arcuate nucleus (ARC). Bilateral microimplants containing senktide induced a dramatic surge-like increase in LH when given in the POA similar to that seen with RCh treatment. By contrast, senktide treatment in the ARC resulted in a much smaller but significant increase in LH concentrations suggestive of an effect on tonic secretion. The possible role of POA and RCh NK3R activation in the LH surge was next tested by treating ewes with SB222200, an NK3R antagonist, in each area during an oestradiol-induced LH surge. SB222200 in the RCh, but not in the POA, reduced the LH surge amplitude by approximately 40% compared to controls, indicating that NK3R activation in the former region is essential for full expression of the pre-ovulatory LH surge. Based on these data, we propose that the actions of NKB in the RCh are an important component of the pre-ovulatory LH surge in ewes.
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Affiliation(s)
- K L Porter
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
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24
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Roland AV, Moenter SM. Reproductive neuroendocrine dysfunction in polycystic ovary syndrome: insight from animal models. Front Neuroendocrinol 2014; 35:494-511. [PMID: 24747343 PMCID: PMC4175187 DOI: 10.1016/j.yfrne.2014.04.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/15/2014] [Accepted: 04/09/2014] [Indexed: 12/23/2022]
Abstract
Polycystic ovary syndrome (PCOS) is a common endocrinopathy with elusive origins. A clinically heterogeneous disorder, PCOS is likely to have multiple etiologies comprised of both genetic and environmental factors. Reproductive neuroendocrine dysfunction involving increased frequency and amplitude of gonadotropin-releasing hormone (GnRH) release, as reflected by pulsatile luteinizing hormone (LH) secretion, is an important pathophysiologic component in PCOS. Whether this defect is primary or secondary to other changes in PCOS is unclear, but it contributes significantly to ongoing reproductive dysfunction. This review highlights recent work in animal models, with a particular emphasis on the mouse, demonstrating the ability of pre- and postnatal steroidal and metabolic factors to drive changes in GnRH/LH pulsatility and GnRH neuron function consistent with the observed abnormalities in PCOS. This work has begun to elucidate how a complex interplay of ovarian, metabolic, and neuroendocrine factors culminates in this syndrome.
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Affiliation(s)
- Alison V Roland
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Suzanne M Moenter
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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25
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Carranza A, Faya M, Merlo ML, Batista P, Gobello C. Effect of GnRH analogs in postnatal domestic cats. Theriogenology 2014; 82:138-43. [DOI: 10.1016/j.theriogenology.2014.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 11/30/2022]
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