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Benitah KC, Kavaliers M, Ossenkopp KP. The enteric metabolite, propionic acid, impairs social behavior and increases anxiety in a rodent ASD model: Examining sex differences and the influence of the estrous cycle. Pharmacol Biochem Behav 2023; 231:173630. [PMID: 37640163 DOI: 10.1016/j.pbb.2023.173630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/10/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
Research suggests that certain gut and dietary factors may worsen behavioral features of autism spectrum disorder (ASD). Treatment with propionic acid (PPA) has been found to create both brain and behavioral responses in rats that are characteristic of ASD in humans. A consistent male bias in human ASD prevalence has been observed, and several sex-differential genetic and hormonal factors have been suggested to contribute to this bias. The majority of PPA studies in relation to ASD focus on male subjects; research examining the effects of PPA in females is scarce. The present study includes two experiments. Experiment 1 explored sex differences in the effects of systemic administration of PPA (500 mg/kg, ip) on adult rodent social behavior and anxiety (light-dark test). Experiment 2 investigated differential effects of systemic administration of PPA (500 mg/kg) on social behavior and anxiety in relation to fluctuating estrogen and progesterone levels during the adult rodent estrous cycle. PPA treatment impaired social behavior and increased anxiety in females to the same degree in comparison to PPA-treated males. As well, females treated with PPA in their diestrus phase did not differ significantly in comparison to females administered PPA in their proestrus phase, in terms of reduced social behavior and increased anxiety.
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Affiliation(s)
- Katie C Benitah
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Martin Kavaliers
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; Department of Psychology, University of Western Ontario, London, Ontario, Canada; Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario, Canada
| | - Klaus-Peter Ossenkopp
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; Department of Psychology, University of Western Ontario, London, Ontario, Canada.
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2
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Moeller JS, Bever SR, Finn SL, Phumsatitpong C, Browne MF, Kriegsfeld LJ. Circadian Regulation of Hormonal Timing and the Pathophysiology of Circadian Dysregulation. Compr Physiol 2022; 12:4185-4214. [PMID: 36073751 DOI: 10.1002/cphy.c220018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Circadian rhythms are endogenously generated, daily patterns of behavior and physiology that are essential for optimal health and disease prevention. Disruptions to circadian timing are associated with a host of maladies, including metabolic disease and obesity, diabetes, heart disease, cancer, and mental health disturbances. The circadian timing system is hierarchically organized, with a master circadian clock located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus and subordinate clocks throughout the CNS and periphery. The SCN receives light information via a direct retinal pathway, synchronizing the master clock to environmental time. At the cellular level, circadian rhythms are ubiquitous, with rhythms generated by interlocking, autoregulatory transcription-translation feedback loops. At the level of the SCN, tight cellular coupling maintains rhythms even in the absence of environmental input. The SCN, in turn, communicates timing information via the autonomic nervous system and hormonal signaling. This signaling couples individual cellular oscillators at the tissue level in extra-SCN brain loci and the periphery and synchronizes subordinate clocks to external time. In the modern world, circadian disruption is widespread due to limited exposure to sunlight during the day, exposure to artificial light at night, and widespread use of light-emitting electronic devices, likely contributing to an increase in the prevalence, and the progression, of a host of disease states. The present overview focuses on the circadian control of endocrine secretions, the significance of rhythms within key endocrine axes for typical, homeostatic functioning, and implications for health and disease when dysregulated. © 2022 American Physiological Society. Compr Physiol 12: 1-30, 2022.
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Affiliation(s)
- Jacob S Moeller
- Graduate Group in Endocrinology, University of California, Berkeley, California, USA
| | - Savannah R Bever
- Department of Psychology, University of California, Berkeley, California, USA
| | - Samantha L Finn
- Department of Psychology, University of California, Berkeley, California, USA
| | | | - Madison F Browne
- Department of Psychology, University of California, Berkeley, California, USA
| | - Lance J Kriegsfeld
- Graduate Group in Endocrinology, University of California, Berkeley, California, USA.,Department of Psychology, University of California, Berkeley, California, USA.,Department of Integrative Biology, University of California, Berkeley, California, USA.,The Helen Wills Neuroscience Institute, University of California, Berkeley, California, USA
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3
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Stenhouse C, Seo H, Wu G, Johnson GA, Bazer FW. Insights into the Regulation of Implantation and Placentation in Humans, Rodents, Sheep, and Pigs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1354:25-48. [PMID: 34807435 DOI: 10.1007/978-3-030-85686-1_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Precise cell-specific spatio-temporal molecular signaling cascades regulate the establishment and maintenance of pregnancy. Importantly, the mechanisms regulating uterine receptivity, conceptus apposition and adhesion to the uterine luminal epithelia/superficial glandular epithelia and, in some species, invasion into the endometrial stroma and decidualization of stromal cells, are critical prerequisite events for placentation which is essential for the appropriate regulation of feto-placental growth for the remainder of pregnancy. Dysregulation of these signaling cascades during this critical stage of pregnancy can lead to pregnancy loss, impaired growth and development of the conceptus, and alterations in the transplacental exchange of gasses and nutrients. While many of these processes are conserved across species, significant variations in the molecular mechanisms governing maternal recognition of pregnancy, conceptus implantation, and placentation exist. This review addresses the complexity of key mechanisms that are critical for the establishment and maintenance of a successful pregnancy in humans, rodents, sheep, and pigs. Improving understanding of the molecular mechanisms governing these processes is critical to enhancing the fertility and reproductive health of humans and livestock species.
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Affiliation(s)
- Claire Stenhouse
- Department of Animal Science and Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA
| | - Heewon Seo
- Department of Animal Science and Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA
| | - Guoyao Wu
- Department of Animal Science and Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA
| | - Gregory A Johnson
- Department of Animal Science and Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA
| | - Fuller W Bazer
- Department of Animal Science and Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA.
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Khant Aung Z, Grattan DR, Ladyman SR. Pregnancy-induced adaptation of central sensitivity to leptin and insulin. Mol Cell Endocrinol 2020; 516:110933. [PMID: 32707081 DOI: 10.1016/j.mce.2020.110933] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 06/22/2020] [Accepted: 06/29/2020] [Indexed: 02/07/2023]
Abstract
Pregnancy is a time of increased food intake and fat deposition in the mother, and adaptations of glucose homeostasis to meet the energy demands of the growing fetus. As part of these adaptations, leptin and insulin concentrations increase in the maternal circulation during pregnancy. Central effects of leptin and insulin, however, are counterproductive to pregnancy, as increased action of these hormones in the brain lead to suppression of food intake. To prevent this, it is well documented that pregnancy induces a state of leptin- and insulin-insensitivity in the brain, particularly the hypothalamus, in a range of species. While the mechanisms underlying leptin- or insulin-insensitivity during pregnancy vary between species, there is evidence of reduced transport into the brain, impaired activation of intracellular signalling pathways, including reduced leptin receptor expression, and attenuated activation of downstream neuronal pathways, especially for leptin insensitivity. Pregnancy-induced changes in prolactin, growth hormone and leptin are discussed in terms of their role in mediating this reduced response to leptin and insulin.
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Affiliation(s)
- Z Khant Aung
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - D R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1010, New Zealand
| | - S R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, 9016, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, 1010, New Zealand.
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5
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Sexual EDC-ucation: What we Have Learned About Endocrine-Disrupting Chemicals and Reproduction. CURRENT SEXUAL HEALTH REPORTS 2020. [DOI: 10.1007/s11930-020-00269-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Creeth HDJ, John RM. The placental programming hypothesis: Placental endocrine insufficiency and the co-occurrence of low birth weight and maternal mood disorders. Placenta 2020; 98:52-59. [PMID: 33039032 DOI: 10.1016/j.placenta.2020.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 12/21/2022]
Abstract
Polypeptide hormones and steroid hormones, either expressed by the placenta or dependant on the placenta for their synthesis, are key to driving adaptations in the mother during pregnancy that support growth in utero. These adaptations include changes in maternal behaviour that take place in pregnancy and after the birth to ensure that offspring receive appropriate care and nutrition. Placentally-derived hormones implicated in the programming of maternal caregiving in rodents include prolactin-related hormones and steroid hormones. Neuromodulators produced by the placenta may act directly on the fetus to support brain development. A number of imprinted genes function antagonistically in the placenta to regulate the development of key placental endocrine lineages expressing these hormones. Gain-in-expression of the normally maternally expressed gene Phlda2 or loss-of-function of the normally paternally expressed gene Peg3 results in fewer endocrine cells in the placenta, and pups are born low birth weight. Importantly, wild type dams carrying these genetically altered pups display alterations in their behaviour with decreased focus on nurturing (Phlda2) or heightened anxiety (Peg3). These same genes may regulate placental hormones in human pregnancies, with the potential to influence birth weight and maternal mood. Consequently, the aberrant expression of imprinted genes in the placenta may underlie the reported co-occurrence of low birth weight with maternal prenatal depression.
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Affiliation(s)
- H D J Creeth
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK
| | - R M John
- Biomedicine Division, School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.
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Ladyman SR, Hackwell ECR, Brown RSE. The role of prolactin in co-ordinating fertility and metabolic adaptations during reproduction. Neuropharmacology 2019; 167:107911. [PMID: 32058177 DOI: 10.1016/j.neuropharm.2019.107911] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 12/30/2022]
Abstract
Mammalian pregnancy and lactation is accompanied by a period of infertility that takes place in the midst of a sustained increase in food intake. Indeed, successful reproduction in females is dependent on co-ordination of the distinct systems that regulate reproduction and metabolism. Rather than arising from different mechanisms during pregnancy and lactation, we propose that elevations in lactogenic hormones (predominant among these being prolactin and the placental lactogens), are ideally placed to influence both of these systems at the appropriate time. We review the literature examining the impacts of lactogens on fertility and energy homeostasis in the virgin state, during pregnancy and lactation and potential long-term impacts of reproductive experience. Taken together, the literature indicates that duration and pattern of lactogen exposure is a vital factor in the ability of these hormones to alter reproduction and food intake. Transient increases in prolactin, as typically seen in healthy virgin females and males, are unable to exert lasting impacts. Importantly, both suppression of fertility and increased food intake are only observed following exposure to chronically-elevated levels of lactogens. Physiologically, the only time this pattern of lactogenic secretion is maintained in the healthy female is during pregnancy and lactation, when co-ordination between these regulatory systems emerges. This article is part of the special issue on 'Neuropeptides'.
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Affiliation(s)
- Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Eleni C R Hackwell
- Centre for Neuroendocrinology and Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Rosemary S E Brown
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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8
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Behura SK, Dhakal P, Kelleher AM, Balboula A, Patterson A, Spencer TE. The brain-placental axis: Therapeutic and pharmacological relevancy to pregnancy. Pharmacol Res 2019; 149:104468. [PMID: 31600597 PMCID: PMC6944055 DOI: 10.1016/j.phrs.2019.104468] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/23/2019] [Accepted: 09/27/2019] [Indexed: 12/22/2022]
Abstract
The placenta plays a critical role in mammalian reproduction. Although it is a transient organ, its function is indispensable to communication between the mother and fetus, and supply of nutrients and oxygen to the growing fetus. During pregnancy, the placenta is vulnerable to various intrinsic and extrinsic conditions which can result in increased risk of fetal neurodevelopmental disorders as well as fetal death. The placenta controls the neuroendocrine secretion in the brain as a means of adaptive processes to safeguard the fetus from adverse programs, to optimize fetal development and other physiological changes necessary for reproductive success. Although a wealth of information is available on neuroendocrine functions in pregnancy, they are largely limited to the regulation of hypothalamus-pituitary-adrenal/gonad (HPA/ HPG) axis, particularly the oxytocin and prolactin system. There is a major gap in knowledge on systems-level functional interaction between the brain and placenta. In this review, we aim to outline the current state of knowledge about the brain-placental axis with description of the functional interactions between the placenta and the maternal and fetal brain. While describing the brain-placental interactions, a special emphasis has been given on the therapeutics and pharmacology of the placental receptors to neuroligands expressed in the brain during gestation. As a key feature of this review, we outline the prospects of integrated pharmacogenomics, single-cell sequencing and organ-on-chip systems to foster priority areas in this field of research. Finally, we remark on the application of precision genomics approaches to study the brain-placental axis in order to accelerate personalized medicine and therapeutics to treat placental and fetal brain disorders.
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Affiliation(s)
- Susanta K Behura
- Division of Animal Sciences, University of Missouri, United States; Informatics Institute, University of Missouri, United States.
| | - Pramod Dhakal
- Division of Animal Sciences, University of Missouri, United States
| | | | - Ahmed Balboula
- Division of Animal Sciences, University of Missouri, United States
| | - Amanda Patterson
- Division of Animal Sciences, University of Missouri, United States; Department of Obstetrics, Gynecology and Women's Health, University of Missouri, United States
| | - Thomas E Spencer
- Division of Animal Sciences, University of Missouri, United States; Department of Obstetrics, Gynecology and Women's Health, University of Missouri, United States
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Augustine RA, Knowles PJ, Khant Aung Z, Grattan DR, Ladyman SR. Impaired hypothalamic leptin sensitivity in pseudopregnant rats treated with chronic prolactin to mimic pregnancy. J Neuroendocrinol 2019; 31:e12702. [PMID: 30803074 DOI: 10.1111/jne.12702] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/27/2019] [Accepted: 02/20/2019] [Indexed: 02/04/2023]
Abstract
Pregnancy in rodents is associated with hyperphagia, increased fat deposition, elevated leptin concentrations and insensitivity to the satiety action of leptin. To investigate the hormonal mechanisms involved in the development of this state of pregnancy-induced leptin resistance, we have used a pseudopregnancy rat model. We have previously demonstrated that pseudopregnant rats have a normal feeding response to leptin, although, if pseudopregnancy is extended using chronic i.c.v. ovine prolactin infusion along with progesterone implants, then leptin no longer suppresses food intake. The present study aimed to investigate the effect of chronically high lactogen levels, as seen in mid-pregnancy, on leptin-induced activation of hypothalamic Janus kinase/signal transducer and activator of transcription (JAK/STAT) signal transduction and mRNA expression of leptin (LepR-B) and prolactin (Prlr-L) receptors, using pseudopregnant rats chronically infused with ovine prolactin. Groups of virgin (dioestrous) and pseudopregnant rats were treated with chronic i.c.v. infusion of either prolactin (2.5 μg μL-1 h-1 for 5 days) or vehicle (artificial cerebrospinal fluid [aCSF]) via a minipump connected to a cannula surgically implanted into the lateral ventricle. Rats were fasted overnight and then received an i.c.v. injection of leptin (400 ng) or vehicle (aCSF) and were perfused 30 minutes later. In chronic vehicle-infused pseudopregnant rats, i.c.v. leptin increased the number of phosphorylated STAT3 positive cells in the arcuate nucleus and ventromedial nucleus (VMH) of the hypothalamus, similar to all acute-leptin treated virgin groups. This effect of leptin, however, was not observed in the pseudopregnant rats that were chronically infused with prolactin. A quantitative polymerase chain reaction analysis also showed decreased expression of LepR-B in the arcuate and VMH nuclei, as well as decreased Prlr-L in the arcuate nucleus of prolactin-infused "extended pseudopregnancy" rats. These data suggest that the attenuation of the leptin-induced suppression of food intake caused by chronically high lactogen levels in pseudopregnant rats is associated with impaired leptin-induced activation of the JAK/STAT pathway in specific hypothalamic nuclei.
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Affiliation(s)
- Rachael A Augustine
- Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Penelope J Knowles
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Zin Khant Aung
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - David R Grattan
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Sharon R Ladyman
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
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Augustine RA, Seymour AJ, Campbell RE, Grattan DR, Brown CH. Integrative neuro-humoral regulation of oxytocin neuron activity in pregnancy and lactation. J Neuroendocrinol 2018; 30. [PMID: 29323764 DOI: 10.1111/jne.12569] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/07/2018] [Indexed: 02/02/2023]
Abstract
Oxytocin is required for normal birth and lactation. Oxytocin is synthesised by hypothalamic supraoptic and paraventricular nuclei neurons and is released into the circulation from the posterior pituitary gland. Under basal conditions, circulating oxytocin levels are relatively constant but during birth and lactation, pulsatile oxytocin release triggers rhythmic contraction of the uterus during birth and milk ejection during suckling. Oxytocin levels are principally determined by the pattern of action potential firing that is, in turn, determined by the interplay between the intrinsic properties of the oxytocin neurons, regulation of their excitability by surrounding glia as well as by synaptic drive from their afferent inputs. During birth and suckling, oxytocin neurons fire high-frequency bursts of action potentials that are coordinated across the population of neurons and these bursts underpin the pulsatile secretion of oxytocin required for normal birth and lactation. Neuroglial regulation of oxytocin neurons changes during pregnancy to favour burst firing. However, these changes still require afferent input activity to drive activity. While it has long been known that noradrenergic inputs to oxytocin neurons are activated during birth and lactation, the involvement of other afferent inputs is less clear. Here, we provide a brief overview of the current understanding of the mechanisms that regulate oxytocin neuron activity during pregnancy and lactation, and focus on recent evidence from our laboratory identifying an input that increases kisspeptin production to excite oxytocin neurons in late pregnancy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Rachael A Augustine
- Department of Physiology Brain Health Research Centre, Centre for Neuroendocrinology
| | - Alexander J Seymour
- Department of Physiology Brain Health Research Centre, Centre for Neuroendocrinology
| | - Rebecca E Campbell
- Department of Physiology Brain Health Research Centre, Centre for Neuroendocrinology
| | - David R Grattan
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Colin H Brown
- Department of Physiology Brain Health Research Centre, Centre for Neuroendocrinology
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11
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Abstract
The posterior pituitary gland secretes oxytocin and vasopressin (the antidiuretic hormone) into the blood system. Oxytocin is required for normal delivery of the young and for delivery of milk to the young during lactation. Vasopressin increases water reabsorption in the kidney to maintain body fluid balance and causes vasoconstriction to increase blood pressure. Oxytocin and vasopressin secretion occurs from the axon terminals of magnocellular neurons whose cell bodies are principally found in the hypothalamic supraoptic nucleus and paraventricular nucleus. The physiological functions of oxytocin and vasopressin depend on their secretion, which is principally determined by the pattern of action potentials initiated at the cell bodies. Appropriate secretion of oxytocin and vasopressin to meet the challenges of changing physiological conditions relies mainly on integration of afferent information on reproductive, osmotic, and cardiovascular status with local regulation of magnocellular neurons by glia as well as intrinsic regulation by the magnocellular neurons themselves. This review focuses on the control of magnocellular neuron activity with a particular emphasis on their regulation by reproductive function, body fluid balance, and cardiovascular status. © 2016 American Physiological Society. Compr Physiol 6:1701-1741, 2016.
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Affiliation(s)
- Colin H Brown
- Brain Health Research Centre, Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, New Zealand
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12
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Stathopoulos AM, Helena CV, Cristancho-Gordo R, Gonzalez-Iglesias AE, Bertram R. Influence of dynorphin on estradiol- and cervical stimulation-induced prolactin surges in ovariectomized rats. Endocrine 2016; 53:585-94. [PMID: 27038317 DOI: 10.1007/s12020-016-0938-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/21/2016] [Indexed: 11/28/2022]
Abstract
Prolactin is an anterior pituitary hormone necessary for fertility, pregnancy maintenance, lactation, and aspects of maternal behavior. In rodents, there is a surge of prolactin on the afternoon of proestrus, and a semi-circadian pattern of prolactin surges during early pregnancy, with a diurnal and nocturnal surge every day. Both of these patterns can be replicated in ovariectomized rats. A prior study demonstrated that central antagonism of κ-opioid receptors, the target of dynorphin, largely abolished the nocturnal prolactin surge in pregnant rats. We build on this to determine whether dynorphin, perhaps from the arcuate population that co-express kisspeptin, neurokinin B, and dynorphin (KNDy neurons), also contributes to the estradiol- or cervical stimulation-induced surges in ovariectomized rats. Ovariectomized rats were treated with either estradiol or cervical stimulation to induce prolactin surge(s). Blood samples were taken around the expected surge time to determine the effect of either acute κ-opioid receptor antagonism or previous chemical ablation of the KNDy population on prolactin levels. Dynorphin antagonism does significantly disrupt the nocturnal prolactin surge, but it does not contribute to the estradiol-induced surge. Chemical ablation of KNDy neurons had opposite effects; ablation of 40 % of the KNDy neurons had no impact on the nocturnal prolactin surge, while a somewhat larger ablation significantly reduced the size of the estradiol-induced surge. We conclude that dynorphin is likely a controlling factor for the nocturnal surge induced by cervical stimulation, and that other KNDy neuron products must play a role in the estradiol-induced surge.
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Affiliation(s)
- Andrea M Stathopoulos
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Cleyde V Helena
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Ruth Cristancho-Gordo
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Arturo E Gonzalez-Iglesias
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Richard Bertram
- Program in Neuroscience and Departments of Mathematics, Florida State University, Tallahassee, FL, 32306, USA.
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13
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deCatanzaro D. Sex steroids as pheromones in mammals: the exceptional role of estradiol. Horm Behav 2015; 68:103-16. [PMID: 25125222 DOI: 10.1016/j.yhbeh.2014.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 12/18/2022]
Abstract
This article is part of a Special Issue (Chemosignals and Reproduction). Whether from endogenous or exogenous sources, 17β-estradiol (E2) has very powerful influences over mammalian female reproductive physiology and behavior. Given its highly lipophilic nature and low molecular mass, E2 readily enters excretions and can be absorbed from exogenous sources via nasal, cutaneous, and other modes of exposure. Indeed, systemic injection of tritiated estradiol ((3)H-E2) into a male mouse or bat has been shown to produce significant levels of radioactivity in the reproductive tissues and brain of cohabiting female conspecifics. Bioactive E2 and other steroids are naturally found in male mouse urine and other excretions, and males actively direct their urine at proximate females. Very low doses of E2 can mimic the Bruce effect (disruption of peri-implantation pregnancy by novel males), the Vandenbergh effect (early reproductive maturation induced by novel males), and male-induced estrus and ovulation. Males' capacities to induce the Bruce and Vandenbergh effects can both be diminished by manipulations that reduce their urinary E2. Uterine dynamics during the Bruce and Vandenbergh effects are consistent with the actions of E2. Collectively, these data demonstrate a critical role of male-sourced E2 in these major mammalian pheromonal effects.
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Affiliation(s)
- Denys deCatanzaro
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
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Nakagawa S, Shimada M, Yanaka K, Mito M, Arai T, Takahashi E, Fujita Y, Fujimori T, Standaert L, Marine JC, Hirose T. The lncRNA Neat1 is required for corpus luteum formation and the establishment of pregnancy in a subpopulation of mice. Development 2014; 141:4618-27. [PMID: 25359727 PMCID: PMC4302932 DOI: 10.1242/dev.110544] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neat1 is a non-protein-coding RNA that serves as an architectural component of the nuclear bodies known as paraspeckles. Although cell-based studies indicate that Neat1 is a crucial regulator of gene expression, its physiological relevance remains unclear. Here, we find that Neat1 knockout (KO) mice stochastically fail to become pregnant despite normal ovulation. Unilateral transplantation of wild-type ovaries or the administration of progesterone partially rescued the phenotype, suggesting that corpus luteum dysfunction and concomitant low progesterone were the primary causes of the decreased fertility. In contrast to the faint expression observed in most of the adult tissues, Neat1 was highly expressed in the corpus luteum, and the formation of luteal tissue was severely impaired in nearly half of the Neat1 KO mice. These observations suggest that Neat1 is essential for the formation of the corpus luteum and for the subsequent establishment of pregnancy under a suboptimal condition that has not yet been identified.
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Affiliation(s)
- Shinichi Nakagawa
- RNA Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Masayuki Shimada
- Laboratory of Reproductive Endocrinology, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima 739-8528, Japan
| | - Kaori Yanaka
- RNA Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Mari Mito
- RNA Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takashi Arai
- Support Unit for Animal Resources Development, Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Eiki Takahashi
- Support Unit for Animal Resources Development, Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Youko Fujita
- Women's Clinic Oizumi-Gakuen, Higashi-Oizumi, Tokyo 178-0063, Japan
| | - Toshihiko Fujimori
- Division of Embryology, National Institute for Basic Biology (NIBB), Okazaki 444-8787, Japan
| | - Laura Standaert
- Laboratory for Molecular Cancer Biology, Center for the Biology of Disease, VIB, Leuven 3000, Belgium Laboratory for Molecular Cancer Biology, Center of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Jean-Christophe Marine
- Laboratory for Molecular Cancer Biology, Center for the Biology of Disease, VIB, Leuven 3000, Belgium Laboratory for Molecular Cancer Biology, Center of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
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15
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Miller BH, Takahashi JS. Central circadian control of female reproductive function. Front Endocrinol (Lausanne) 2014; 4:195. [PMID: 24478756 PMCID: PMC3898595 DOI: 10.3389/fendo.2013.00195] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/06/2013] [Indexed: 02/01/2023] Open
Abstract
Over the past two decades, it has become clear just how much of our physiology is under the control of the suprachiasmatic nucleus (SCN) and the cell-intrinsic molecular clock that ticks with a periodicity of approximately 24 h. The SCN prepares our digestive system for meals, our adrenal axis for the stress of waking up in the morning, and the genes expressed in our muscles when we prepare to exercise. Long before molecular studies of genes such as Clock, Bmal1, and the Per homologs were possible, it was obvious that female reproductive function was under strict circadian control at every level of the hypothalamic-pituitary-gonadal axis, and in the establishment and successful maintenance of pregnancy. This review highlights our current understanding of the role that the SCN plays in regulating female reproductive physiology, with a special emphasis on the advances made possible through the use of circadian mutant mice.
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Affiliation(s)
- Brooke H Miller
- Departments of Psychiatry and Medicine, University of Florida College of Medicine , Gainesville, FL , USA
| | - Joseph S Takahashi
- Department of Neuroscience, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center , Dallas, TX , USA
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16
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Borrow AP, Cameron NM. The role of oxytocin in mating and pregnancy. Horm Behav 2012; 61:266-76. [PMID: 22107910 DOI: 10.1016/j.yhbeh.2011.11.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 10/10/2011] [Accepted: 11/01/2011] [Indexed: 12/23/2022]
Abstract
The hormone oxytocin (OT) is released both centrally and peripherally during and after mating. Although research in humans suggests a central role in sexuality, the most reliable findings to date involve peripheral activation. This review will discuss these results and will particularly focus on understanding the most recent findings from fMRI data and the effects of exogenous peripheral OT administration. We will then consider hypotheses of the roles played by central and systemic OT release as well as their control and modulation in the female, summarizing recent findings from animal research. Finally, we will discuss the contribution of OT to the initiation of pregnancy in rodents. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.
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Affiliation(s)
- Amanda P Borrow
- Center for Development and Behavioral Neuroscience, Psychology Department, Binghamton University-SUNY, Binghamton, NY 13902-6000, USA
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17
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Abstract
In the female rat, a complex interplay of both stimulatory and inhibitory hypothalamic factors controls the secretion of prolactin. Prolactin regulates a large number of physiological processes from immunity to stress. Here, we have chosen to focus on the control of prolactin secretion in the female rat in response to suckling, mating and ovarian steroids. In all three of these states, dopamine, released from neurones in the mediobasal hypothalamus, is a potent inhibitory signal regulating prolactin secretion. Early research has determined that the relief of dopaminergic tone is not sufficent to account for the full surge of prolactin secretion observed in response to the suckling stimulus, launching a search for possible prolactin-releasing factors. This research has subsequently broadened to include searching for prolactin-releasing factors controlling prolactin secretion after mating or ovarian steroids. A great deal of literature has suggested that this prolactin-releasing factor may include oxytocin. Oxytocin receptors are present on lactotrophs. These oxytocin receptors respond to exogenous oxytocin and antagonism of endogenous oxytocin inhibits lactotroph activity. In addition, the pattern of oxytocin neuronal activity and oxytocin release correlate with the release of prolactin. Here, we suggest not only that oxytocin is stimulating prolactin secretion, but also that prolactin secretion is controlled by a complex network of positive (oxytocin) and negative (dopamine) feedback loops. We discuss the available literature and attempt to describe the circuitry we believe may be responsible for controlling prolactin secretion.
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Affiliation(s)
- Jessica E. Kennett
- Department of Biology, University of Virginia, 485 McCormick Road, Charlottesville, VA 22903
| | - De’Nise T. McKee
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, LaJolla, CA 92093-0674
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18
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Helena CV, Cristancho-Gordo R, Gonzalez-Iglesias AE, Tabak J, Bertram R, Freeman ME. Systemic oxytocin induces a prolactin secretory rhythm via the pelvic nerve in ovariectomized rats. Am J Physiol Regul Integr Comp Physiol 2011; 301:R676-81. [PMID: 21677274 DOI: 10.1152/ajpregu.00176.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have shown previously that an intravenous injection of oxytocin (OT) in ovariectomized (OVX) rats initiates a circadian rhythm of prolactin (PRL) secretion similar to that observed after cervical stimulation (CS). In this study, we investigated the pathway through which OT triggers the PRL rhythm. We first tested whether an intracerebroventricular injection of OT could trigger the PRL secretory rhythm. As it did not, we injected OT intravenously while an OT receptor antagonist was infused intravenously. This antagonist completely abolished the PRL surges, suggesting that a peripheral target of OT is necessary for triggering the PRL rhythm. We hypothesized that OT may induce PRL release, which would be transported into the brain and trigger the rhythm. In agreement with this, OT injection increased circulating PRL by 5 min. To test whether this acute increase in PRL release would induce the PRL rhythm, we compared the effect of intravenously administered thyrotropin-releasing hormone (TRH) and OT. Although TRH injection also increased PRL to a comparable level after 5 min, only OT-injected animals expressed the PRL secretory rhythm. Motivated by prior findings that bilateral resection of the pelvic nerve blocks CS-induced pseudopregnancy and OT-induced facilitation of lordosis, we then hypothesized that the OT signal may be transmitted through the pelvic nerve. In fact, OT injection failed to induce a PRL secretory rhythm in pelvic-neurectomized animals, suggesting that the integrity of the pelvic nerve is necessary for the systemic OT induction of the PRL secretory rhythm in OVX rats.
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Affiliation(s)
- Cleyde V Helena
- Departments of Biological Science, Biomedical Research Facility, Florida State University, Tallahassee, FL, USA.
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19
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Egli M, Leeners B, Kruger THC. Prolactin secretion patterns: basic mechanisms and clinical implications for reproduction. Reproduction 2010; 140:643-54. [DOI: 10.1530/rep-10-0033] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Prolactin (PRL) is one of the most versatile hormones in the mammalian body affecting reproductive, sexual, metabolic, immune, and other functions. It is therefore not surprising that the neural control of PRL secretion is complex, involving the coordinated actions of several hypothalamic nuclei. A plethora of experimental data exists on the hypothalamic control of hormone secretion under various physiological stimuli. There have been even mathematical models and computer studies published, which help to understand the complex hypothalamic–pituitary network. Nevertheless, the putative role of PRL for human reproduction still has to be clarified. Here, we review data on the underlying mechanisms controlling PRL secretion using both experimental and mathematical approaches. These investigations primarily focus on rhythmic secretion in rats during early pregnancy or pseudopregnancy, and they point to the important role of oxytocin as a crucial PRL-releasing factor. Recent data on human studies and their theoretical and clinical implications are reviewed as well. In particular, studies demonstrating a sustained PRL surge after sexual climax in males and females are presented, indicating possible implications for both sexual satiation and reproductive functions. Taking these data together, there is evidence for the hypothesis that the PRL surge induced by sexual activity, together with the altered PRL rhythmic pattern, is important for successful initialization of pregnancy not only in rodents but also possibly in humans. However, further investigations are needed to clarify such a role in humans.
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20
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Northrop LE, Polston EK, Erskine MS. Noradrenergic nuclei that receive sensory input during mating and project to the ventromedial hypothalamus play a role in mating-induced pseudopregnancy in the female rat. J Neuroendocrinol 2010; 22:1061-71. [PMID: 20673300 PMCID: PMC3063002 DOI: 10.1111/j.1365-2826.2010.02049.x] [Citation(s) in RCA: 7] [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] [Indexed: 11/29/2022]
Abstract
In female rats, vaginal-cervical stimulation (VCS) received during mating induces bicircadian prolactin surges that are required for the maintenance of pregnancy or pseudopregnancy (PSP). The neural circuits that transmit VCS inputs to the brain have not been fully described, although mating stimulation is known to activate medullary noradrenergic cell groups that project to the forebrain. In response to VCS, these neurones release noradrenaline within the ventrolateral division of the ventromedial hypothalamus (VMHvl) and the posterodorsal medial amygdala (MePD), two forebrain sites that are implicated in the initiation of PSP. Noradrenaline receptor activation within the VMHvl is both necessary and sufficient for PSP induction, suggesting that noradrenaline acting within the VMHvl is particularly important in mediating the effects of VCS towards the establishment of PSP. We therefore investigated whether or not endogenous, VCS-induced noradrenaline release within the VMHvl is involved in PSP induction in the rat. Before the receipt of sufficient mating stimulation to induce PSP, a retrograde neurotoxin, dopamine-β-hydroxylase-saporin (DBH-SAP), was infused bilaterally into the either the VMHvl or the MePD to selectively destroy afferent noradrenergic nuclei in the brainstem. DBH-SAP infusions into the VMHvl lesioned mating-responsive noradrenergic neurones in A1 and A2 medullary nuclei and reduced the incidence of PSP by 50%. Infusions of DBH-SAP into the MePD had no effect on the subsequent induction of PSP. These results suggest that VCS is conveyed to mating-responsive forebrain areas by brainstem noradrenergic neurones, and that the activity of noradrenergic cells projecting to the VMHvl is involved in the induction of PSP.
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Affiliation(s)
- L E Northrop
- Department of Biology, Boston University, Boston, MA, USA. Reproductive Medicine Associates of New Jersey, Morristown, NJ, USA
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21
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Bertram R, Helena CV, Gonzalez-Iglesias AE, Tabak J, Freeman ME. A tale of two rhythms: the emerging roles of oxytocin in rhythmic prolactin release. J Neuroendocrinol 2010; 22:778-84. [PMID: 20456600 PMCID: PMC3152303 DOI: 10.1111/j.1365-2826.2010.02012.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Hormone secretion often occurs in a pulsatile manner. In this review, we discuss two rhythms of in vivo prolactin release in female rats and the ongoing research that we and others have performed aiming to understand the mechanisms underlying them. The peptide hormone oxytocin appears to play an important role in both rhythms. One rhythm occurs during the first half of pregnancy, but can also be induced in ovariectomised rats. This is characterised by a circadian pattern with two prolactin surges per day. Two methods for triggering this rhythm are discussed, each utilising a unique physiological pathway that includes oxytocin action, presumably on pituitary lactotrophs. The second rhythm occurs during the oestrous cycle and is characterised by a surge of prolactin on the afternoon of pro-oestrus. We discuss recent findings that oxytocin is more effective at stimulating prolactin release from lactotrophs taken from animals on the afternoon of pro-oestrus than from those of animals on the morning of dioestrus 1, raising the possibility that this hormone plays a physiological role in the regulation of prolactin secretion during the oestrous cycle.
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Affiliation(s)
- R Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, FL, USA.
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22
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Melatonin and the ovary: physiological and pathophysiological implications. Fertil Steril 2009; 92:328-43. [DOI: 10.1016/j.fertnstert.2008.05.016] [Citation(s) in RCA: 246] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 05/02/2008] [Accepted: 05/05/2008] [Indexed: 10/21/2022]
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23
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Helena CV, McKee DT, Bertram R, Walker AM, Freeman ME. The rhythmic secretion of mating-induced prolactin secretion is controlled by prolactin acting centrally. Endocrinology 2009; 150:3245-51. [PMID: 19282380 PMCID: PMC2703506 DOI: 10.1210/en.2009-0095] [Citation(s) in RCA: 16] [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
Artificial copulomimetic cervical stimulation (CS) induces an immediate release of oxytocin (OT) and prolactin (PRL) followed by a daily PRL rhythm characterized by nocturnal and diurnal surges. Although we have shown that the initial release of PRL is induced by the immediate release of OT, we tested whether the PRL that is released in response to CS is responsible for the initiation and maintenance of the subsequent PRL surges. Thus, we injected OVX rats centrally or peripherally with ovine PRL (oPRL) at 2200 h. Central oPRL induced PRL surges in OVX rats that were similar in size and timing to those of CS rats, whereas peripheral oPRL induced surges that were of smaller amplitude and delayed. We then infused a PRL antagonist (S179D, 0.1 ng/h) centrally into OVX and OVX-CS rats and measured the release of endogenous PRL and the activity of neuroendocrine dopaminergic neurons. Central infusion of S179D did not influence basal PRL secretion in OVX rats but prevented the expression of the CS-induced PRL surges and the accompanying noontime increase of CS-induced dopaminergic activity when continued for 3 d. However, central infusion of S179D only on the day of CS did not prevent the daily rhythm of PRL surges. These results demonstrate that PRL acts centrally to induce the PRL rhythm and that PRL in the brain is essential for the maintenance but not for the initiation of the CS-induced rhythmic PRL surges.
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Affiliation(s)
- Cleyde V Helena
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4340, USA
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24
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Kennett JE, Poletini MO, Fitch CA, Freeman ME. Antagonism of oxytocin prevents suckling- and estradiol-induced, but not progesterone-induced, secretion of prolactin. Endocrinology 2009; 150:2292-9. [PMID: 19106214 PMCID: PMC2671903 DOI: 10.1210/en.2008-1611] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In female rats, estradiol (E(2)) and suckling induce prolactin (PRL) secretion. This involves inhibition of hypothalamic dopaminergic tone and stimulation by a PRL-releasing hormone, possibly oxytocin (OT). Infusing an OT antagonist (OTA) i.v., we evaluated the role of OT on suckling- and E(2)-induced PRL secretion. Three days after parturition at 0900 h, lactating dams were fitted with 24-h osmotic minipumps filled with saline or OTA. On d 5 of lactation, pups were separated from their dams for 6 h. Immediately or 20 min after the resumption of suckling, dam trunk blood was collected. Also, ovariectomized (OVX) rats were treated with E(2) (OVE) and OTA at 1000 h on d 1. Blood samples were obtained from 1300 to 2100 h on d 2 for PRL measurements. Additionally, OVX rats were evaluated on d 2 after receiving progesterone (P(4)). OTA blocked suckling and E(2)-induced release of PRL but not that induced by E(2)+P(4). Pups from treated dams failed to gain weight when allowed to nurse for 20 min on d 5 but gained more than 7 g when nursed on d 7 of lactation, indicating that the OTA was active 48 h later. Western blot analysis showed that E(2) treatment increased OT receptors in the anterior pituitary when compared with OVX animals. No further increase was observed in response to the P(4), suggesting that the enhancing effect of P(4) on E(2)-induced PRL release may act through mechanisms independent of OT. These data demonstrate the role of OT in the control of suckling and steroid-induced PRL secretion.
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Affiliation(s)
- Jessica E Kennett
- Department of Biological Science, and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, USA
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25
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Xu R, Nelson CM, Muschler JL, Veiseh M, Vonderhaar BK, Bissell MJ. Sustained activation of STAT5 is essential for chromatin remodeling and maintenance of mammary-specific function. ACTA ACUST UNITED AC 2009; 184:57-66. [PMID: 19139262 PMCID: PMC2615090 DOI: 10.1083/jcb.200807021] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Epithelial cells, once dissociated and placed in two-dimensional (2D) cultures, rapidly lose tissue-specific functions. We showed previously that in addition to prolactin, signaling by laminin-111 was necessary to restore functional differentiation of mammary epithelia. Here, we elucidate two additional aspects of laminin-111 action. We show that in 2D cultures, the prolactin receptor is basolaterally localized and physically segregated from its apically placed ligand. Detachment of the cells exposes the receptor to ligation by prolactin leading to signal transducers and activators of transcription protein 5 (STAT5) activation, but only transiently and not sufficiently for induction of milk protein expression. We show that laminin-111 reorganizes mammary cells into polarized acini, allowing both the exposure of the prolactin receptor and sustained activation of STAT5. The use of constitutively active STAT5 constructs showed that the latter is necessary and sufficient for chromatin reorganization and β-casein transcription. These results underscore the crucial role of continuous laminin signaling and polarized tissue architecture in maintenance of transcription factor activation, chromatin organization, and tissue-specific gene expression.
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Affiliation(s)
- Ren Xu
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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26
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Yang JJ, Larsen CM, Grattan DR, Erskine MS. Mating-induced neuroendocrine responses during pseudopregnancy in the female mouse. J Neuroendocrinol 2009; 21:30-9. [PMID: 19094091 DOI: 10.1111/j.1365-2826.2008.01803.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pseudopregnancy (PSP) is a neuroendocrine reflex triggered by vaginocervical stimulation similar to the neuroendocrine response of early pregnancy and is characterised by short-term neural activity, resulting in long-term neuroendocrine responses that cause repeated release of pituitary prolactin (PRL) over many days. PSP is a useful model to study how somatosensory input is transduced in the brain into neuroendocrine responses, and has been extensively characterised in rats. With increasing use of mice as an experimental model, however, and to allow use of transgenic mice to investigate mechanisms of this sensory response, it is important to characterise the principal neuroendocrine response of pseudopregnancy in this species. The present study aimed to examine the induction and neuroendocrine responses of PSP in mice using vasectomised stud males, to investigate mating-induced changes in vaginal cytology, uterine growth, and PRL secretion, and to map certain aspects of somatosensory transduction by assessing the neural activity marker FOS. Unlike the induction of pseudopregnancy in rats, which can be induced simply by multiple intromissions from a male or artificial mechanical stimulation of the cervix, PSP induction in mice required the receipt of an ejaculation from a male. In mice that received PSP-inducible mating stimuli, FOS expression was observed in a slightly different range of brain regions than has been observed in rats, with increases in the bed nucleus of the stria terminalis, medial preoptic area, and ventromedial hypothalamus, but not in limbic areas examined. Moreover, PSP mice expressed a single diurnal PRL surge on day 6 of PSP. Thus, the data demonstrate important species differences in the neuroendocrine mechanisms activated in response to a mating stimulus in mice compared with rats. A clear understanding of the species-specific response will be required in interpreting research into the reproductive biology of this species.
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Affiliation(s)
- J J Yang
- Department of Biology, Boston University, Boston, MA, USA.
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27
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Abstract
The neuroendocrine control of prolactin secretion is unlike that of any other pituitary hormone. It is predominantly inhibited by the hypothalamus and, in the absence of a regulatory feedback hormone, it acts directly in the brain to suppress its own secretion. In addition to this short-loop feedback action in the brain, prolactin has been reported to influence a wide range of other brain functions. There have been few attempts to rationalise why a single hormone might exert such a range of distinct and seemingly unrelated neuroendocrine functions. In this review, we highlight some of the original studies that first characterised the unusual features of prolactin neuroendocrinology, and then attempt to identify areas of new progress and/or controversy. Finally, we discuss a hypothesis that provides a unifying explanation for the pleiotrophic actions of prolactin in the brain.
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Affiliation(s)
- D R Grattan
- Centre for Neuroendocrinology and Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand.
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28
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Augustine RA, Grattan DR. Induction of central leptin resistance in hyperphagic pseudopregnant rats by chronic prolactin infusion. Endocrinology 2008; 149:1049-55. [PMID: 18063686 DOI: 10.1210/en.2007-1018] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pregnancy in rats is associated with hyperphagia, increased fat deposition, and elevated plasma leptin concentrations. Elevated leptin would be expected to inhibit food intake, but hypothalamic leptin resistance develops around midpregnancy, allowing hyperphagia to be maintained and excess energy to be stored as fat in preparation for future metabolic demands of lactation. To investigate the hormonal mechanisms inducing leptin resistance during pregnancy, the anorectic response to leptin was examined during pseudopregnancy. Pseudopregnant rats have identical hormonal profiles to early pregnancy, but no placenta formation, allowing differentiation of maternal and placental hormone effects on appetite. To investigate the effect of leptin on food intake, d-9 pseudopregnant rats were injected with leptin (4 microg) via an intracerebroventricular (icv) cannula, and then food intake was measured 24 h later. Pseudopregnant rats were hyperphagic but had normal anorectic responses to leptin. We therefore hypothesized that a longer exposure time to high concentrations of progesterone might be required to mimic the leptin resistance that occurs on d 14 of pregnancy. Pseudopregnant rats were given progesterone to prolong pseudopregnancy beyond the time that leptin resistance develops during pregnancy. However, rats remained responsive to icv leptin. To model the placental lactogen secretion that occurs during pregnancy, pseudopregnant rats were given progesterone and chronic icv ovine prolactin infusion. Central icv injection of leptin had no effect on food intake in pseudopregnant rats receiving chronic ovine prolactin. These results suggest that chronically high lactogen levels, secreted by the placenta during the second half of pregnancy, induce central leptin resistance.
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Affiliation(s)
- Rachael A Augustine
- Centre for Neuroendocrinology and Department of Anatomy and Structural Biology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
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29
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Oakes SR, Rogers RL, Naylor MJ, Ormandy CJ. Prolactin regulation of mammary gland development. J Mammary Gland Biol Neoplasia 2008; 13:13-28. [PMID: 18219564 DOI: 10.1007/s10911-008-9069-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2007] [Accepted: 01/02/2008] [Indexed: 10/22/2022] Open
Abstract
Mammary morphogenesis is orchestrated with other reproductive events by pituitary-driven changes to the systemic hormone environment, initiating the formation of a mammary ductal network during puberty and the addition of secretory alveoli during pregnancy. Prolactin is the major driver of development during pregnancy via regulation of ovarian progesterone production (in many species) and direct effects on mammary epithelial cells (in all species). Together these hormones regulate two aspects of development that are the subject of intense interest: (1) a genomic regulatory network that integrates many additional spatial and temporal cues to control gene expression and (2), the activity of a stem and progenitor cell hierarchy. Amalgamation of these two aspects will increase our understanding of cell proliferation and differentiation within the mammary gland, with clear application to our attempts to control breast cancer. Here we focus on providing an over-view of prolactin action during development of the model murine mammary gland.
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Affiliation(s)
- Samantha R Oakes
- Development group, Cancer Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW, 2010, Australia
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30
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McKee DT, Poletini MO, Bertram R, Freeman ME. Oxytocin action at the lactotroph is required for prolactin surges in cervically stimulated ovariectomized rats. Endocrinology 2007; 148:4649-57. [PMID: 17615142 PMCID: PMC2085361 DOI: 10.1210/en.2007-0646] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cervical stimulation induces two daily rhythmic prolactin surges, nocturnal and diurnal, which persist for several days. We have shown that a bolus injection of oxytocin initiates a similar prolactin rhythm, which persists despite low levels of oxytocin after injection. This suggests that oxytocin may trigger the cervical stimulation-induced rhythmic prolactin surges. To investigate this hypothesis, we infused an oxytocin antagonist that does not cross the blood-brain barrier for 24 h before and after cervical stimulation and measured serum prolactin. We also measured dopaminergic neuronal activity because mathematical modeling predicted that this activity would be low in the presence of the oxytocin antagonist. We thus tested this hypothesis by measuring dopaminergic neuronal activity in the tuberoinfundibular, periventricular hypophyseal, and tuberohypophyseal dopaminergic neurons. Infusion of oxytocin antagonist before cervical stimulation abolished prolactin surges, and infusion of oxytocin antagonist after cervical stimulation abolished the diurnal and significantly decreased the nocturnal surges of prolactin. The rhythmic prolactin surges returned after the clearance of the oxytocin antagonist. Hypothalamic dopaminergic activity was elevated in antiphase with prolactin surges, and the antiphase elevation was abolished by the oxytocin antagonist in the tuberoinfundibular and tuberohypophyseal dopaminergic neurons, consistent with the mathematical model. These findings suggest that oxytocin is a physiologically relevant prolactin-releasing factor. However, the cervical stimulation-induced prolactin surges are maintained even in the absence of oxytocin actions at the lactotroph, which strongly suggests the maintenance of prolactin surges are not dependent upon oxytocin actions at the pituitary gland.
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Affiliation(s)
- De'Nise T McKee
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
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31
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Cameron NM, Carey P, Erskine MS. Medullary noradrenergic neurons release norepinephrine in the medial amygdala in females in response to mating stimulation sufficient for pseudopregnancy. Brain Res 2006; 1022:137-47. [PMID: 15353223 DOI: 10.1016/j.brainres.2004.07.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2004] [Indexed: 11/17/2022]
Abstract
In the female rat, stimuli from the uterine cervix and vagina are carried to the brain areas involved in the mating-induced pseudopregnancy (PSP) response via the ventral noradrenergic bundle. Noradrenergic neurons projecting through this tract synapse in many forebrain areas including the amygdala, and neurons in the posterodorsal medial amygdala (MePD) are activated following mating. The goal of this experiment was to investigate whether norepinephrine (NE) is released into the MePD after mating using microdialysis and to determine the origin of this release. Ovariectomized estrogen- and progesterone-treated rats were implanted unilaterally with guide cannulae aimed at the MePD. Females were placed with males until they received 15 intromissions (15I), 5 intromissions (5I) or 15 mounts-without-intromission (MO). Dialysate samples collected every 20 min for 2 h before to 3 h after mating were analyzed for NE using HPLC with electrochemical detection. A significant increase in mean NE release in the MePD was seen at 80 min after mating onset in females receiving 15I, and no increase was seen in animals receiving 5I or MO. The time of peak NE release varied in 15I animals from 60 to 160 min after mating. Mean baseline levels of NE did not differ between groups. The retrograde tracer FluoroGold (FG), administered through the probe after cessation of dialysis sampling, was observed within identified noradrenergic cells primarily within the A1 and A2 cell groups. Infusion of anti-dopamine-beta-hydroxylase-saporin (DBH-SAP) into the MePD lesioned noradrenergic neurons located in the A1 and A2 cell groups. Because high levels of NE release occurred in the MePD only after the females received a number of intromissions sufficient to induce PSP, these results suggest that NE release within the MePD may be important for the establishment of PSP.
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Affiliation(s)
- Nicole M Cameron
- Department of Biology, Boston University, 5 Cummington St., Boston, MA 02215, USA
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32
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Bertram R, Egli M, Toporikova N, Freeman ME. A mathematical model for the mating-induced prolactin rhythm of female rats. Am J Physiol Endocrinol Metab 2006; 290:E573-82. [PMID: 16467488 PMCID: PMC1543714 DOI: 10.1152/ajpendo.00428.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
For the first 10 days of pregnancy and the first 12 days of pseudopregnancy, the secretion of prolactin (PRL) from pituitary lactotrophs is rhythmic, with two surges/day. This rhythm can also be triggered by bolus injection of oxytocin (OT). We describe a mathematical model for the initiation, maintenance, and termination of the OT-induced PRL rhythm. In our model, the mechanism for this circadian rhythm is mutual interaction between lactotrophs and neuroendocrine dopamine (DA) neurons. This rhythm is, under normal lighting conditions, entrained by the suprachiasmatic nucleus (SCN) but persists in the absence of input from the SCN. We postulate that OT injection triggers the rhythm by activating a population of bistable hypothalamic neurons that innervate and inhibit DA neurons. The bistable nature of these neurons allows them to act as a memory device, maintaining the rhythm long after OT has been cleared from the blood. The mechanism for this memory device and the arguments supporting it are detailed with computer simulations. Finally, we consider potential targets for a rhythm-terminating factor and make predictions that may be used to determine which mechanism is operational in terminating the OT- or mating-induced PRL rhythm.
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Affiliation(s)
- Richard Bertram
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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33
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Becker JB, Arnold AP, Berkley KJ, Blaustein JD, Eckel LA, Hampson E, Herman JP, Marts S, Sadee W, Steiner M, Taylor J, Young E. Strategies and methods for research on sex differences in brain and behavior. Endocrinology 2005; 146:1650-73. [PMID: 15618360 DOI: 10.1210/en.2004-1142] [Citation(s) in RCA: 609] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Female and male brains differ. Differences begin early during development due to a combination of genetic and hormonal events and continue throughout the lifespan of an individual. Although researchers from a myriad of disciplines are beginning to appreciate the importance of considering sex differences in the design and interpretation of their studies, this is an area that is full of potential pitfalls. A female's reproductive status and ovarian cycle have to be taken into account when studying sex differences in health and disease susceptibility, in the pharmacological effects of drugs, and in the study of brain and behavior. To investigate sex differences in brain and behavior there is a logical series of questions that should be answered in a comprehensive investigation of any trait. First, it is important to determine that there is a sex difference in the trait in intact males and females, taking into consideration the reproductive cycle of the female. Then, one must consider whether the sex difference is attributable to the actions of gonadal steroids at the time of testing and/or is sexually differentiated permanently by the action of gonadal steroids during development. To answer these questions requires knowledge of how to assess and/or manipulate the hormonal condition of the subjects in the experiment appropriately. This article describes methods and procedures to assist scientists new to the field in designing and conducting experiments to investigate sex differences in research involving both laboratory animals and humans.
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Affiliation(s)
- Jill B Becker
- Department of Psychology, University of Michigan, 525 East University, Ann Arbor, MI 48109, USA.
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34
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Miller BH, Olson SL, Turek FW, Levine JE, Horton TH, Takahashi JS. Circadian clock mutation disrupts estrous cyclicity and maintenance of pregnancy. Curr Biol 2004; 14:1367-73. [PMID: 15296754 PMCID: PMC3756147 DOI: 10.1016/j.cub.2004.07.055] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Revised: 05/28/2004] [Accepted: 06/09/2004] [Indexed: 11/30/2022]
Abstract
Classic experiments have shown that ovulation and estrous cyclicity are under circadian control and that surgical ablation of the suprachiasmatic nuclei (SCN) results in estrous acyclicity in rats. Here, we characterized reproductive function in the circadian Clock mutant mouse and found that the circadian Clock mutation both disrupts estrous cyclicity and interferes with the maintenance of pregnancy. Clock mutant females have extended, irregular estrous cycles, lack a coordinated luteinizing hormone (LH) surge on the day of proestrus, exhibit increased fetal reabsorption during pregnancy, and have a high rate of full-term pregnancy failure. Clock mutants also show an unexpected decline in progesterone levels at midpregnancy and a shortened duration of pseudopregnancy, suggesting that maternal prolactin release may be abnormal. In a second set of experiments, we interrogated the function of each level of the hypothalamic-pituitary-gonadal (HPG) axis in order to determine how the Clock mutation disrupts estrous cyclicity. We report that Clock mutants fail to show an LH surge following estradiol priming in spite of the fact that hypothalamic levels of gonadotropin-releasing hormone (GnRH), pituitary release of LH, and serum levels of estradiol and progesterone are all normal in Clock/Clock females. These data suggest that Clock mutants lack an appropriate circadian daily-timing signal required to coordinate hypothalamic hormone secretion. Defining the mechanisms by which the Clock mutation disrupts reproductive function offers a model for understanding how circadian genes affect complex physiological systems.
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Affiliation(s)
- Brooke H. Miller
- Department of Neurobiology & Physiology, Northwestern University, Evanston, IL 60208
- Northwestern University Institute for Neuroscience
| | - Susan Losee Olson
- Department of Neurobiology & Physiology, Northwestern University, Evanston, IL 60208
| | - Fred W. Turek
- Department of Neurobiology & Physiology, Northwestern University, Evanston, IL 60208
- Northwestern University Institute for Neuroscience
| | - Jon E. Levine
- Department of Neurobiology & Physiology, Northwestern University, Evanston, IL 60208
- Northwestern University Institute for Neuroscience
| | - Teresa H. Horton
- Department of Neurobiology & Physiology, Northwestern University, Evanston, IL 60208
| | - Joseph S. Takahashi
- Department of Neurobiology & Physiology, Northwestern University, Evanston, IL 60208
- Northwestern University Institute for Neuroscience
- Howard Hughes Medical Institute
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35
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Yang SP, Voogt JL. Mating-activated nitric oxide-producing neurons in specific brain regions in the female rat. Brain Res 2002; 950:79-87. [PMID: 12231231 DOI: 10.1016/s0006-8993(02)03004-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nitric oxide (NO)-containing neurons have been localized in various parts of the central nervous system including the hypothalamus. NO plays an important role in the regulation of reproductive activities including sexual behavior and pituitary hormone secretion. To test the hypothesis that NO-containing neurons in specific brain areas may respond to the stimulus of mating and participate in integrating the tactile information in the hypothalamus, this study used Fos as a marker of neuronal activity. Proestrous rats receiving intromissions (mated group) from males or mounts-without-intromission (mounted group) were sacrificed along with rats taken directly from their home cage (control group) 90 min after the beginning of mating or mounting. NOergic neurons were labeled by histochemical reaction for nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d). The presence of activated NO-producing (double-stained NADPH-d/Fos) neurons was quantitatively assessed in several brain areas before and after mating. The results showed that mating-with-intromissions induced a significant increase in the percentage of NADPH-d/Fos colabeled neurons in the medial preoptic area (mPOA) and the magnocellular component of the paraventricular nucleus (PVNm) compared to mounts-without-intromission or control treatment. Both mating and mounting induced Fos expression in NADPH-d-positive cells in the ventromedial nucleus of hypothalamus (VMN). In contrast, the expression of Fos in the NADPH-d-positive neurons in the supraoptic nucleus (SON) and the parvocellular portion of the paraventricular nucleus (PVNp) was not influenced by either mating or mounting although abundant NO-containing neurons were found in the two brain areas. The second experiment of the study examined whether NOergic neurons in these brain areas are influenced directly by estrogen by determining the number of NADPH-d-positive neurons that contained the estrogen receptor alpha (ERalpha), the classical ER. Double labeled NADPH-d/ERalpha neurons were observed in several brain areas including the mPOA and VMN while few, if any, NADPH-d-positive neurons in the SON, PVNm or PVNp contained ERalpha. The results suggest that the activated NOergic neurons in these brain areas may be involved in processing and integrating the mating stimulus. Further investigation is required to determine the physiological role of the mating-activated NOergic activity in specific mating-induced changes in reproductive neuroendocrinology.
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Affiliation(s)
- Shu-Ping Yang
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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36
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Kawaminami M, Yoshida M, Moriai Y, Kurusu S, Hashimoto I. Adrenal influence on the persistence of pseudopregnancy in rats. Endocr J 2002; 49:357-62. [PMID: 12201221 DOI: 10.1507/endocrj.49.357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The effect of adrenalectomy on the duration of pseudopregnancy was investigated in rats. When adrenalectomy was performed three days before cervical stimulation or when it was done on the first day (day 1, day of estrus) or day 2 of pseudopregnancy, the duration of the pseudopregnancy was significantly prolonged (3.0, 2.5 and 1.8 days respectively). This effect of adrenalectomy was not seen when operation was delayed until day 4 of pseudopregnancy. Adrenalectomy on day 2 of pseudopregnancy significantly increased prolactin (PRL) release at the time of the nocturnal PRL surge (5:00) on day 7. When rats were ovariectomized simultaneously with adrenalectomy on day 1, the stimulating effect of adrenalectomy on PRL release was more evident. The effect of active immunization against corticosterone on the continuation of pseudopregnancy was also examined. Neutralization of plasma corticosterone extended the duration of pseudopregnancy and the binding activity of the antiserum positively correlated with the length of continuing diestrus (P < 0.05). These results indicate the negative effect of the adrenal glands, which is probably due to corticosterone, on PRL release in pseudopregnant rats and that the early relief of this inhibition extends the duration of pseudopregnancy.
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Affiliation(s)
- Mitsumori Kawaminami
- School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034-8628, Japan
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37
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Bethea CL. Editorial: large lessons from little lactotropes. Endocrinology 2001; 142:4170-2. [PMID: 11564669 DOI: 10.1210/endo.142.10.8489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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38
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Osada T, Watanabe G, Sakaki Y, Takeuchi T. Puromycin-sensitive aminopeptidase is essential for the maternal recognition of pregnancy in mice. Mol Endocrinol 2001; 15:882-93. [PMID: 11376108 DOI: 10.1210/mend.15.6.0644] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Maternal recognition of pregnancy in rodents requires semicircadian surges of hypophyseal PRL secretion during early gestation, which are required for the formation of the corpus luteum of pregnancy (CLP). Here we show that puromycin-sensitive aminopeptidase (Psa)-deficient mice display female infertility that results from impaired formation of CLP. Transplantation of mutant ovaries into normal females restored fertility but not vice versa. Psa-deficient females revealed no semicircadian surges of PRL induced after mating stimuli. Pregnancy in the mutant females was restored by grafting intact pituitaries to elevate circulating levels of PRL. Psa is thus required for the appearance of the semicircadian surges of PRL secretion that are crucial for maintaining pregnancy in rodents.
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Affiliation(s)
- T Osada
- Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194-8511, Japan
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39
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NMDA-mediated activation of the medial amygdala initiates a downstream neuroendocrine memory responsible for pseudopregnancy in the female rat. J Neurosci 2001. [PMID: 11356898 DOI: 10.1523/jneurosci.21-11-04104.2001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In female rats, genitosensory stimulation received during mating initiates twice-daily prolactin (PRL) surges, a neuroendocrine response that is the hallmark of early pregnancy or pseudopregnancy (P/PSP). Nocturnal and diurnal PRL surges are expressed repeatedly for up to 2 weeks after copulation, suggesting that a neuroendocrine memory for vaginocervical stimulation (VCS) is established at the time of mating. These studies investigated whether the processing and retention of VCS involves acute glutamatergic activation or de novo protein synthesis within the medial nucleus of the amygdala (MEA), a VCS-responsive brain site that is implicated in P/PSP initiation. Pharmacological activation of the MEA with the glutamate agonist, NMDA, initiated nocturnal PRL surges, causing a PSP state in females that had not received VCS. P/PSP initiation by mating was prevented by intra-amygdalar infusion of the NMDA receptor antagonist, 2-amino-5-phosphonopentanoic acid (AP-5), provided that it was administered before mating. AP-5 treatment also disrupted mating-induced c-fos expression in the principle bed nucleus of the stria terminalis and the ventrolateral division of the ventromedial hypothalamic nucleus, but not in the medial or anteroventral periventricular preoptic nuclei. Neither P/PSP nor downstream cellular activation was prevented when a protein synthesis inhibitor, anisomycin, was administered to the MEA. The results indicate that MEA cells are critical to the early processing of VCS through NMDA channel activation, rapidly conveying information to downstream hypothalamic cell groups that modulate neuroendocrine function.
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40
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41
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Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus controls circadian rhythmicity in mammals (for reviews, see Refs. 33 and 59). Responses modulated by the SCN are numerous and include rhythms in sleep/wake cycles, locomotor, gnawing and general activity, temperature, ingestive behavior, and rhythms of hormonal and peptide secretions. Though a great deal is known about the neuroanatomical organization of the SCN, many elements of the structure-function relationships remain to be discovered. For example, it is not known which cellular components of the SCN function as driving pacemakers or which output signal(s) of these pacemakers are important for each of its functions. While some signals from pacemaker cells reach target regions by neural efferents, there is also evidence that rhythmic responses can be controlled by diffusible signals. This article reviews output signals from the SCN. The data available suggest that neural efferents are not necessary for the control of locomotor activity rhythms. Evidence that a diffusible signal is sufficient to restore activity rhythms in SCN-lesioned animals is described. Finally, possible physiological mechanisms for diffusible signals are suggested.
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Affiliation(s)
- J LeSauter
- Department of Psychology, Barnard College, New York, NY, USA
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42
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MAEKAWA F, YAMANOUCHI K. Differential Effects of Dorsal Raphe Nucleus Lesions on Pseudopregnancy Induced by Reserpine or Vaginal Stimulation in Female Rats. J Reprod Dev 1998. [DOI: 10.1262/jrd.44.337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Fumihiko MAEKAWA
- Neuroendocrinology, Department of Basic Human Sciences, School of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan
| | - Korehito YAMANOUCHI
- Neuroendocrinology, Department of Basic Human Sciences, School of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan
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43
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Inano H, Suzuki K. Radiation-induced mammary tumorigenesis in pseudopregnant rats mated with vasectomized partners. Cancer Lett 1997; 116:241-5. [PMID: 9215869 DOI: 10.1016/s0304-3835(97)00194-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Pseudopregnancy was induced in Wistar-MS female rats by mating with male rats 1 month after vasectomy. Pseudopregnant rats received whole-body irradiation with 2.6 Gy gamma-rays at day 7 of pseudopregnancy and were then implanted with a DES pellet as a tumor promoter. In the control groups, virgin 2.5 month-old rats, and normal pregnant rats at day 7 of pregnancy were also exposed to the same dose of radiation. The incidence of mammary tumors in rats irradiated in pseudopregnancy (52.6%) was significantly higher than that in the irradiated virgin rats (20.8%), but was not significantly different from that observed in rats irradiated in normal pregnancy (66.7%). The appearance of the first mammary tumor in the rats irradiated in pseudopregnancy occurred 4 months earlier than that in the normal pregnancy group. The proportion of adenocarcinomas in total tumors was 16.7, 0 and 38.5% in rats irradiated in pseudopregnancy, virgin and pregnancy groups, respectively. The incidence of adenocarcinomas was not significantly different among the three groups.
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Affiliation(s)
- H Inano
- The First Research Group, National Institute of Radiological Sciences, Inage-ku, Chiba-shi, Japan
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44
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Fernandes PA, Koodoo SR, Wodzicki AM, Allardice JG, McCoshen JA. Maternal Prolactin Secretion Is Phasic During Induced Term and Post-Term Labor. ACTA ACUST UNITED AC 1997. [DOI: 10.1177/107155769700400206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | | | | | | | - John A. McCoshen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Manitoba, Hospital, Winnipeg, Manitoba, Canada
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45
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Telleria CM, Deis RP. Reproductive function in rats after mifepristone-induced termination of pregnancy. Contraception 1996; 53:185-90. [PMID: 8689885 DOI: 10.1016/0010-7824(96)00009-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The effect of mifepristone, a potent progesterone receptor antagonist, on the reproductive function during early pregnancy in rats was examined. A single dose of this drug (10 mg/kg) was injected s.c. at 1200 h on day 4 (Group 1), day 7 (Group II) or day 10 (Group III) of pregnancy. Gestation was interrupted and the vaginal cytology showed a typical proestrus condition two days after mifepristone treatment in all groups. When compared with cycling proestrus rats, serum LH concentrations at 1800 h in the mifepristone-induced proestrus were lower in Group I, similar in Group II and higher in Group III, and serum prolactin (PRL) values were lower in Group I, but not different in Groups II and III. Serum progesterone levels were higher in the three experimental groups when compared with cycling proestrus rats, and similar to that of pregnant rats. Rats in Group I showed a significantly lower sexual receptivity and ovulation rate when compared with Groups II and III or cycling proestrus rats. Most of the mifepristone-treated rats that copulated during the night of the induced proestrus did not become pregnant and showed a delayed pseudopregnancy-like condition. These results indicate that mifepristone administered in a single dose to early pregnant rats terminates pregnancy and induces a proestrus condition two days after treatment followed by successful postovulatory contraception. The mifepristone-induced proestrus is characterized by a differential pattern of serum LH, PRL and progesterone concentrations, mating behavior and ovulation rates, depending on the day of pregnancy when mifepristone is administered.
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Affiliation(s)
- C M Telleria
- Laboratorio de Reproducción y Lactancia, LARLAC-CONICET, Mendoza, Argentina
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46
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Maekawa F, Yamanouchi K. Effect of deprivation of serotonin by p-chlorophenylalanine on induction and maintenance of pseudopregnancy in female rats. Brain Res Bull 1996; 39:317-21. [PMID: 8705320 DOI: 10.1016/0361-9230(95)02117-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The effect of serotonin synthesis inhibitor, p-chlorophenylalanine (PCPA), on induction and maintenance of pseudopregnancy as indicated by deciduoma formation was examined in female rats. Animals were injected with 1 mg/kg b.wt. of reserpine on the day of metestrus, and silk thread was passed through and placed in the left uterine horn 3 days after reserpine to induce deciduoma. PCPA (100 mg/kg b.wt.) was injected daily for 4 days before or after reserpine in 15 and 13 rats, respectively. A single injection of PCPA was administered before reserpine in nine females. In another group of rats (N = 16), instead of PCPA, saline was injected four times before reserpine. Nineteen female rats were treated with reserpine only as a control group. Results showed 89% of the control and 81.3% of the saline-treated females had massive deciduoma in traumatized uterine horn. In contrast, only 33.3% or 46.2% females with daily treatments of PCPA for 4 days before or after reserpine showed positive decidual reaction. In addition, 88.9% of females with single injection of PCPA possessed uterine horns with deciduoma. These results suggest that 4 days of treatment with PCPA eliminate induction and/or maintenance of pseudopregnancy. Thus, some levels of serotonin are required to induce and maintain pseudopregnancy.
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Affiliation(s)
- F Maekawa
- Department of Basic Human Sciences, School of Human Sciences, Waseda University, Saitama, Japan
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47
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Timmerman W, Deinum ME, Poelman RT, Westerink BH, Schuiling GA. Characterisation of the DA-ergic system in the mediobasal hypothalamus: a new approach to simultaneously monitor the release of DA from the TIDA neurons and the PRL secretion from the adenohypophysis in awake rats. Brain Res 1994; 657:275-80. [PMID: 7820628 DOI: 10.1016/0006-8993(94)90977-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The TIDA neurons, which constitute part of the arcuate nucleus-ME complex, play an important inhibitory role in the regulation of the PRL secretion from the adenohypophysis. To simultaneously study the release of DA from the TIDA neurons and the PRL secretion from the adenohypophysis in awake rats, a microdialysis probe was implanted into the MBH together with a permanent heartcannula in male rats. The extracellular levels of DA in the MBH as measured by microdialysis decreased to 25% of basal values after local infusion of TTX (1 mumol/l), indicating that the released DA was directly derived from neuronal activity. DOPAC levels were not affected. This local infusion of TTX into the MBH induced parallel to the immediate decrease in DA levels, a profound increase in PRL concentration in the blood (from 10 to 55 ng/PRL-RP-2/ml) directly after infusion. Thus, the area in which the dialysis probe was inserted indeed included the DA-ergic neurons that regulate the PRL secretion. Evidence for a functional re-uptake system in the MBH was obtained by local infusion of the re-uptake inhibitor nomifensine (5 mumol/l) which induced an increase in DA release to 350% of basal values, without affecting the DOPAC levels. In spite of this increase in DA levels, the PRL concentration in the blood was not affected. In pseudopregnant female rats, relatively high levels of extracellular DA in the MBH were obtained during the interphase during which the PRL levels are low, while lower DA levels were apparent during the phase the spontaneous nocturnal PRL surge normally appears. Taken together, the approach presented in this study, i.e. the simultaneous measurements of DA in the MBH and PRL in the blood, establishes an advanced method enabling studies on the DA-PRL interactions in awake animals.
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Affiliation(s)
- W Timmerman
- Department of Obstetrics and Gynaecology, University of Groningen, The Netherlands
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48
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Li CS, Kaba H, Seto K. Effective induction of pregnancy block by electrical stimulation of the mouse accessory olfactory bulb coincident with prolactin surges. Neurosci Lett 1994; 176:5-8. [PMID: 7970236 DOI: 10.1016/0304-3940(94)90857-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Electrical stimulation (0.33 Hz, 0.2 mA) applied bilaterally to the accessory olfactory bulb (AOB) of newly mated female mice revealed that stimulation for 4 h was sufficient to produce pregnancy block providing stimulation is given for two separate 2-h periods coincident with prolactin surges. Stimulation for two 1-h periods coincident with prolactin surges or two 2-h periods between prolactin surges was without effect. These results indicate that electrical stimulation of the AOB can faithfully reproduce pheromone-induced pregnancy block and support the view that prolactin is the hormone mainly responsible for the olfactory block to pregnancy.
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Affiliation(s)
- C S Li
- Department of Physiology, Kochi Medical School, Japan
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49
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Tekpetey FR, Armstrong DT. Catecholestrogen modulation of steroid production by rat luteal cells: mechanism of action. Mol Cell Endocrinol 1994; 101:49-57. [PMID: 9397936 DOI: 10.1016/0303-7207(94)90218-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study investigated the mechanisms underlying 2-hydroxyestradiol (2-OHE2) effect on luteal steroidogenesis using serum-free cultures of mixed luteal cells from day 8 pseudopregnant rats. Initially, interactions between 2-OHE2 and LH or dibutyryl (db)cAMP on progesterone production were investigated. LH (250 ng/ml) and 2-OHE2 (2.5 microg/ml) had comparable effects on progesterone accumulation, while dbcAMP (5 mM) was more stimulatory. When applied together, 2-OHE2 did not synergize with LH or dbcAMP to further enhance progesterone accumulation. Furthermore, in time course experiments, the dose-dependent effect of 2-OHE2 was to reduce and eventually abolish the time-dependent increase in cAMP accumulation. In contrast LH stimulated cAMP accumulation at all times. Experiments in which cells were co-treated with 2-OHE2, 22-OH-cholesterol and cyanoketone, or with 2-OHE2 and 22-OH-cholesterol or pregnenolone indicated that 2-OHE2 not only had a stimulatory effect on the cholesterol side-chain cleavage and 3beta-hydroxysteroid dehydrogenase enzymes, but it also appeared to inhibit the 20alpha-hydroxysteroid dehydrogenase leading to a relative increase in progesterone accumulation. Experiments with hormone antagonists suggested that the actions of 2-OHE2 were not mediated by the estrogen, alpha- or beta-adrenergic receptors. The results of this study support the concept of a physiological role for catecholestrogens in rat luteal steroidogenesis.
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Affiliation(s)
- F R Tekpetey
- Department of Physiology, The University of Western Ontario, London, Canada
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Kornberg E, Erskine MS. Effects of differential mating stimulation on the onset of prolactin surges in pseudopregnant rats. Psychoneuroendocrinology 1994; 19:357-71. [PMID: 8047640 DOI: 10.1016/0306-4530(94)90016-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In the female rat, stimulation of the uterine cervix (CS) during mating or by artificial means induces daily diurnal and nocturnal surges in prolactin (PRL) secretion which, in the absence of fertilization, result in an 12-day anestrous period called pseudopregnancy (PSP). The amount or type of mating stimulation received by the female during mating determines whether or not PSP occurs, but it has not yet been determined whether different amounts of mating stimulation can alter the time of onset of PRL surges. The present studies examined the latency in days to the first nocturnal PRL surge following mating. Plasma PRL was measured in samples obtained via intra-atrial catheters at 0200-0500h on the day of estrus (Day 0) and on the subsequent 3 days (Days 1-3). In Experiment 1, proestrus females received mating stimulation which was more than (15 intromissions, 15I) or less than (mounts-without-intromission only, MO) sufficient to induce PSP. Surges were absent in 15I females until Days 1-2 and in MO females on all days. In Experiment 2, females received five intromissions (5I) in paced and nonpaced mating tests, types of mating treatments which were expected to induce PSP in some but not all females. PRL surges were not evident at any sampling time in females that continued to cycle, while PRL surges occurred consistently on Day 2 among PSP females. Among PSP females, those receiving 5I showed significantly higher PRL on Day 0 than did 15I females. In both experiments, plasma progesterone concentrations were not higher in PSP than in non-PSP animals until Day 3. In Experiment 3, PRL levels in single samples obtained by cardiac puncture on Day 0 were similar to those seen in the first two experiments. Thus, PRL secretion at the time of the first postmating nocturnal surge is influenced by the type of CS received some 8-10 h earlier. However, if sufficient CS is received to induce the neural changes of PSP, the nocturnal PRL surges are expressed in an all-or-none fashion by 1-2 days after mating.
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Affiliation(s)
- E Kornberg
- Department of Biology, Boston University, Massachusetts 02215
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