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Gilbert JD, Rossiter SJ, Bennett NC, Faulkes CG. The elusive role of prolactin in the sociality of the naked mole-rat. Horm Behav 2022; 143:105196. [PMID: 35597054 DOI: 10.1016/j.yhbeh.2022.105196] [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: 12/10/2021] [Revised: 04/13/2022] [Accepted: 05/05/2022] [Indexed: 12/01/2022]
Abstract
Despite decades of research into the evolutionary drivers of sociality, we know relatively little about the underlying proximate mechanisms. Here we investigate the potential role of prolactin in the highly social naked mole-rat. Naked mole-rats live in large social groups but, only a small number of individuals reproduce. The remaining non-breeders are reproductively suppressed and contribute to burrow maintenance, foraging, and allo-parental care. Prolactin has well-documented links with reproductive timing and parental behaviour, and the discovery that non-breeding naked mole-rats have unusually high prolactin levels has led to the suggestion that prolactin may help maintain naked mole-rat sociality. To test this idea, we investigated whether urinary prolactin was correlated with cooperative behaviour and aggression. We then administered the prolactin-suppressing drug Cabergoline to eight female non-breeders for eight weeks and assessed the physiology and behaviour of the animals relative to controls. Contrary to the mammalian norm, and supporting previous findings for plasma, we found non-breeders had elevated urinary prolactin concentrations that were similar to breeding females. Further, prolactin levels were higher in heavier, socially dominant non-breeders. Urinary prolactin concentrations did not explain variation in working behaviour or patterns of aggression. Furthermore, females receiving Cabergoline did not show any behavioural or hormonal (progesterone) differences, and urinary prolactin did not appear to be suppressed in individuals receiving Cabergoline. While the results add to the relatively limited literature experimentally manipulating prolactin to investigate its role in reproduction and behaviour, they fail to explain why prolactin levels are high in non-breeding naked mole-rats, or how female non-breeding phenotypes are maintained.
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Affiliation(s)
- James D Gilbert
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom of Great Britain and Northern Ireland.
| | - Stephen J Rossiter
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom of Great Britain and Northern Ireland
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Christopher G Faulkes
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom of Great Britain and Northern Ireland.
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2
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Pereira M, Smiley KO, Lonstein JS. Parental Behavior in Rodents. ADVANCES IN NEUROBIOLOGY 2022; 27:1-53. [PMID: 36169811 DOI: 10.1007/978-3-030-97762-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Members of the order Rodentia are among the best-studied mammals for understanding the patterns, outcomes, and biological determinants of maternal and paternal caregiving. This research has provided a wealth of information but has historically focused on just a few rodents, mostly members of the two Myomorpha families that easily breed and can be studied within a laboratory setting (including laboratory rats, mice, hamsters, voles, gerbils). It is unclear how well this small collection of animals represents the over 2000 species of extant rodents. This chapter provides an overview of the hormonal and neurobiological systems involved in parental care in rodents, with a purposeful eye on providing information known or could be gleaned about parenting in various less-traditional members of Rodentia. We conclude from this analysis that the few commonly studied rodents are not necessarily even representative of the highly diverse members of Myomorpha, let alone other rodent suborders, and that additional laboratory and field studies of members of this order more broadly would surely provide invaluable information toward revealing a more representative picture of the rich diversity in rodent parenting.
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Affiliation(s)
- Mariana Pereira
- Department of Psychological and Brain Sciences, University of Massachusetts, Amherst, MA, USA
| | - Kristina O Smiley
- Centre for Neuroendocrinology & Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Joseph S Lonstein
- Department of Psychology & Neuroscience Program, Michigan State University, East Lansing, MI, USA.
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3
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BASES PSICOBIOLÓGICAS DE LA CORRESPONSABILIDAD PATERNA. REVISTA MÉDICA CLÍNICA LAS CONDES 2021. [DOI: 10.1016/j.rmclc.2021.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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4
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Coen CW, Bennett NC, Holmes MM, Faulkes CG. Neuropeptidergic and Neuroendocrine Systems Underlying Eusociality and the Concomitant Social Regulation of Reproduction in Naked Mole-Rats: A Comparative Approach. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:59-103. [PMID: 34424513 DOI: 10.1007/978-3-030-65943-1_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The African mole-rat family (Bathyergidae) includes the first mammalian species identified as eusocial: naked mole-rats. Comparative studies of eusocial and solitary mole-rat species have identified differences in neuropeptidergic systems that may underlie the phenomenon of eusociality. These differences are found in the oxytocin, vasopressin and corticotrophin-releasing factor (CRF) systems within the nucleus accumbens, amygdala, bed nucleus of the stria terminalis and lateral septal nucleus. As a corollary of their eusociality, most naked mole-rats remain pre-pubertal throughout life because of the presence of the colony's only reproductive female, the queen. To elucidate the neuroendocrine mechanisms that mediate this social regulation of reproduction, research on the hypothalamo-pituitary-gonadal axis in naked mole-rats has identified differences between the many individuals that are reproductively suppressed and the few that are reproductively mature: the queen and her male consorts. These differences involve gonadal steroids, gonadotrophin-releasing hormone-1 (GnRH-1), kisspeptin, gonadotrophin-inhibitory hormone/RFamide-related peptide-3 (GnIH/RFRP-3) and prolactin. The comparative findings in eusocial and solitary mole-rat species are assessed with reference to a broad range of studies on other mammals.
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Affiliation(s)
- Clive W Coen
- Reproductive Neurobiology, Division of Women's Health, Faculty of Life Sciences & Medicine, King's College London, London, UK.
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Melissa M Holmes
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada.,Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada.,Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Christopher G Faulkes
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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5
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Paternal care in rodents: Ultimate causation and proximate mechanisms. RUSSIAN JOURNAL OF THERIOLOGY 2020. [DOI: 10.15298/rusjtheriol.19.1.01] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Storey AE, Alloway H, Walsh CJ. Dads: Progress in understanding the neuroendocrine basis of human fathering behavior. Horm Behav 2020; 119:104660. [PMID: 31883946 DOI: 10.1016/j.yhbeh.2019.104660] [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: 11/25/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 12/18/2022]
Abstract
We outline the progress on the hormonal basis of human paternal behavior during the past twenty years. Advances in understanding the roles of testosterone, prolactin, oxytocin and vasopressin in fathering behavior are described, along with recent research on hormonal interactions, such as those between testosterone and cortisol, and testosterone and the peptide hormones. In addition, we briefly describe the recent leaps forward in elucidating the neurobiological and neuroendocrine basis of fatherhood, made possible by fMRI technology. Emerging from this literature is a developing and complicated story about fatherhood, highlighting the need to further understand the interplay between behavior, physiology, social context, and individual genetic variation. Given the changing roles of parents in many societies, the continued growth of this research area will provide a strong empirical knowledge base about paternal behavior on which to create policies promoting fathers' involvement in their infants' lives.
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Affiliation(s)
- Anne E Storey
- Department of Psychology, Memorial University, St. John's, Newfoundland and Labrador A1B 3X9, Canada.
| | - Hayley Alloway
- Cognitive and Behavioural Ecology Graduate Program, Memorial University, St. John's, Newfoundland and Labrador A1B 3X9, Canada
| | - Carolyn J Walsh
- Department of Psychology, Memorial University, St. John's, Newfoundland and Labrador A1B 3X9, Canada
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Glasper ER, Kenkel WM, Bick J, Rilling JK. More than just mothers: The neurobiological and neuroendocrine underpinnings of allomaternal caregiving. Front Neuroendocrinol 2019; 53:100741. [PMID: 30822428 DOI: 10.1016/j.yfrne.2019.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/21/2019] [Accepted: 02/25/2019] [Indexed: 12/30/2022]
Abstract
In a minority of mammalian species, mothers depend on others to help raise their offspring. New research is investigating the neuroendocrine mechanisms supporting this allomaternal behavior. Several hormones have been implicated in allomaternal caregiving; however, the role of specific hormones is variable across species, perhaps because allomothering independently evolved multiple times. Brain regions involved in maternal behavior in non-human animals, such as the medial preoptic area, are also critically involved in allomaternal behavior. Allomaternal experience modulates hormonal systems, neural plasticity, and behavioral reactivity. In humans, fatherhood-induced decreases in testosterone and increases in oxytocin may support sensitive caregiving. Fathers and mothers activate similar neural systems when exposed to child stimuli, and this can be considered a global "parental caregiving" network. Finally, early work on caregiving by non-kin (e.g., foster parents) suggests reliance on similar mechanisms as biologically-related parents. This article is part of the 'Parental Brain and Behavior' Special Issue.
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Affiliation(s)
- E R Glasper
- Department of Psychology, University of Maryland, 4094 Campus Drive, College Park, MD 20742, USA; Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD 20742, USA.
| | - W M Kenkel
- Kinsey Institute, Indiana University, 150 S. Woodlawn Avenue, Bloomington, IN 47405, USA
| | - J Bick
- Department of Psychology, University of Houston, 4849 Calhoun Road, Houston, TX 77204, USA; Texas Institute for Measurement, Evaluation, and Statistics, University of Houston, 4849 Calhoun Rd, Houston, TX 77204, USA
| | - J K Rilling
- Department of Anthropology, Emory University, 207 Anthropology Building, 1557 Dickey Drive, Atlanta, GA 30322, USA; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 101 Woodruff Circle, Atlanta, GA 30322, USA; Center for Behavioral Neuroscience, Emory University, PO Box 3966, Atlanta, GA 30302, USA; Center for Translational Social Neuroscience, Emory University, 201 Dowman Drive, Atlanta, GA 30322, USA
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8
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Rymer TL, Pillay N. An integrated understanding of paternal care in mammals: lessons from the rodents. J Zool (1987) 2018. [DOI: 10.1111/jzo.12575] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- T. L. Rymer
- School of Animal, Plant and Environmental Sciences; University of the Witwatersrand; Johannesburg South Africa
- College of Science and Engineering; James Cook University; Cairns QLD Australia
- Centre for Tropical Environmental and Sustainability Sciences; James Cook University; Cairns QLD Australia
| | - N. Pillay
- School of Animal, Plant and Environmental Sciences; University of the Witwatersrand; Johannesburg South Africa
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9
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Horrell ND, Hickmott PW, Saltzman W. Neural Regulation of Paternal Behavior in Mammals: Sensory, Neuroendocrine, and Experiential Influences on the Paternal Brain. Curr Top Behav Neurosci 2018; 43:111-160. [PMID: 30206901 DOI: 10.1007/7854_2018_55] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Across the animal kingdom, parents in many species devote extraordinary effort toward caring for offspring, often risking their lives and exhausting limited resources. Understanding how the brain orchestrates parental care, biasing effort over the many competing demands, is an important topic in social neuroscience. In mammals, maternal care is necessary for offspring survival and is largely mediated by changes in hormones and neuropeptides that fluctuate massively during pregnancy, parturition, and lactation (e.g., progesterone, estradiol, oxytocin, and prolactin). In the relatively small number of mammalian species in which parental care by fathers enhances offspring survival and development, males also undergo endocrine changes concurrent with birth of their offspring, but on a smaller scale than females. Thus, fathers additionally rely on sensory signals from their mates, environment, and/or offspring to orchestrate paternal behavior. Males can engage in a variety of infant-directed behaviors that range from infanticide to avoidance to care; in many species, males can display all three behaviors in their lifetime. The neural plasticity that underlies such stark changes in behavior is not well understood. In this chapter we summarize current data on the neural circuitry that has been proposed to underlie paternal care in mammals, as well as sensory, neuroendocrine, and experiential influences on paternal behavior and on the underlying circuitry. We highlight some of the gaps in our current knowledge of this system and propose future directions that will enable the development of a more comprehensive understanding of the proximate control of parenting by fathers.
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Affiliation(s)
- Nathan D Horrell
- Graduate Program in Neuroscience, University of California, Riverside, Riverside, CA, USA
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, USA
| | - Peter W Hickmott
- Graduate Program in Neuroscience, University of California, Riverside, Riverside, CA, USA
- Department of Psychology, University of California, Riverside, Riverside, CA, USA
| | - Wendy Saltzman
- Graduate Program in Neuroscience, University of California, Riverside, Riverside, CA, USA.
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA, USA.
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10
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Kent M, Bell AM. Changes in behavior and brain immediate early gene expression in male threespined sticklebacks as they become fathers. Horm Behav 2018; 97:102-111. [PMID: 29117505 PMCID: PMC5771839 DOI: 10.1016/j.yhbeh.2017.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 10/21/2017] [Accepted: 11/03/2017] [Indexed: 02/04/2023]
Abstract
Motherhood is a period of intense behavioral and brain activity. However, we know less about the neural and molecular mechanisms associated with the demands of fatherhood. Here, we report the results of two experiments designed to track changes in behavior and brain activation associated with fatherhood in male threespined stickleback fish (Gasterosteus aculeatus), a species in which fathers are the sole providers of parental care. In experiment 1, we tested whether males' behavioral reactions to different social stimuli depends on parental status, i.e. whether they were providing parental care. Parental males visited their nest more in response to social stimuli compared to nonparental males. Rates of courtship behavior were high in non-parental males but low in parental males. In experiment 2, we used a quantitative in situ hybridization method to compare the expression of an immediate early gene (Egr-1) across the breeding cycle - from establishing a territory to caring for offspring. Egr-1 expression peaked when the activities associated with fatherhood were greatest (when they were providing care to fry), and then returned to baseline levels once offspring were independent. The medial dorsal telencephalon (basolateral amygdala), lateral part of dorsal telencephalon (hippocampus) and anterior tuberal nucleus (ventral medial hypothalamus) exhibited high levels of Egr-1 expression during the breeding cycle. These results help to define the neural circuitry associated with fatherhood in fishes, and are consistent with the hypothesis that fatherhood - like motherhood - is a period of intense behavioral and neural activity.
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Affiliation(s)
- Molly Kent
- Program in Neuroscience, University of Illinois, Urbana Champaign, United States
| | - Alison M Bell
- School of Integrative Biology, Program in Neuroscience, Program in Ecology, Evolution and Conservation, Institute for Genomic Biology, University of Illinois, Urbana Champaign, United States.
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11
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Zilkha N, Scott N, Kimchi T. Sexual Dimorphism of Parental Care: From Genes to Behavior. Annu Rev Neurosci 2017; 40:273-305. [DOI: 10.1146/annurev-neuro-072116-031447] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Noga Zilkha
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Niv Scott
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037
| | - Tali Kimchi
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
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12
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Kenkel WM, Perkeybile AM, Carter CS. The neurobiological causes and effects of alloparenting. Dev Neurobiol 2017; 77:214-232. [PMID: 27804277 PMCID: PMC5768312 DOI: 10.1002/dneu.22465] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/26/2016] [Accepted: 10/15/2016] [Indexed: 12/21/2022]
Abstract
Alloparenting, defined as care provided by individuals other than parents, is a universal behavior among humans that has shaped our evolutionary history and remains important in contemporary society. Dysfunctions in alloparenting can have serious and sometimes fatal consequences for vulnerable infants and children. In spite of the importance of alloparenting, they still have much to learn regarding the underlying neurobiological systems governing its expression. Here, they review how a lack of alloparental behavior among traditional laboratory species has led to a blind spot in our understanding of this critical facet of human social behavior and the relevant neurobiology. Based on what is known, they draw from model systems ranging from voles to meerkats to primates to describe a conserved set of neuroendocrine mechanisms supporting the expression of alloparental care. In this review we describe the neurobiological and behavioral prerequisites, ontogeny, and consequences of alloparental care. Lastly, they identified several outstanding topics in the area of alloparental care that deserve further research efforts to better advance human health and wellbeing. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 214-232, 2017.
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Affiliation(s)
| | | | - C Sue Carter
- Kinsey Institute, Indiana University, Bloomington, Indiana
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13
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Abstract
Social interactions are essential for animals to reproduce, defend their territory, and raise their young. The conserved nature of social behaviors across animal species suggests that the neural pathways underlying the motivation for, and the execution of, specific social responses are also maintained. Modern tools of neuroscience have offered new opportunities for dissecting the molecular and neural mechanisms controlling specific social responses. We will review here recent insights into the neural circuits underlying a particularly fascinating and important form of social interaction, that of parental care. We will discuss how these findings open new avenues to deconstruct infant-directed behavioral control in males and females, and to help understand the neural basis of parenting in a variety of animal species, including humans. Please also see the video abstract here.
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Affiliation(s)
- Johannes Kohl
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Center for Brain Science, Harvard University, Cambridge, MA, USA
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, London, UK
| | - Anita E. Autry
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Catherine Dulac
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Center for Brain Science, Harvard University, Cambridge, MA, USA
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14
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Hashemian F, Shafigh F, Roohi E. Regulatory role of prolactin in paternal behavior in male parents: A narrative review. J Postgrad Med 2016; 62:182-7. [PMID: 27424551 PMCID: PMC4970346 DOI: 10.4103/0022-3859.186389] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In all mammalian species, a combination of neuroendocrine and experiential factors contributes to the emergence of remarkable behavioral changes observed in parental behavior. Yet, our understanding of neuroendocrine bases of paternal behavior in humans is still preliminary and more research is needed in this area. In the present review, the authors summarized hormonal bases of paternal behavior in both human and nonhuman mammalian species and focused on studies on the regulatory role of prolactin in occurrence of paternal behavior. All peer-reviewed journal articles published before 2015 for each area discussed (parental brain, hormonal bases of maternal behavior, hormonal bases of paternal behavior and the role of prolactin in regulation of paternal behavior in nonhuman mammalian species, hormonal bases of paternal behavior and the role of prolactin in regulation of paternal behavior in humans) were searched by PubMed, Medline, and Scopus for original research and review articles. Publications between 1973 and 2015 were included. Similar to female parents, elevated prolactin levels in new fathers most probably contribute to child-caring behavior and facilitate behavioral and emotional states attributed to child care. Moreover, elevated parental prolactin levels after childbirth decrease the parents' libidos so that they invest more in parental care than in fertility behavior. According to the available clinical studies, elevation in the amounts of prolactin levels after childbirth in male parents are probably associated with paternal behavior observed in humans.
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Affiliation(s)
- F Hashemian
- Department of Clinical Pharmacy, Faculty of Pharmacy, Islamic Azad University, Pharmaceutical Sciences Branch, Tehran, Iran
| | - F Shafigh
- Department of Clinical Pharmacy, Faculty of Pharmacy, Islamic Azad University, Pharmaceutical Sciences Branch, Tehran, Iran
| | - E Roohi
- Department of Clinical Pharmacy, Faculty of Pharmacy, Islamic Azad University, Pharmaceutical Sciences Branch, Tehran, Iran
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15
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Smiley KO, Adkins-Regan E. Prolactin is related to individual differences in parental behavior and reproductive success in a biparental passerine, the zebra finch (Taeniopygia guttata). Gen Comp Endocrinol 2016; 234:88-94. [PMID: 26965952 DOI: 10.1016/j.ygcen.2016.03.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 03/02/2016] [Accepted: 03/06/2016] [Indexed: 11/29/2022]
Abstract
Variation in parental care can lead to important fitness consequences. The endocrine system is known to regulate physiological and behavioral reproductive traits that are important contributors to lifetime reproductive success. However, the hormonal basis of variation in avian parental care is still not well understood. Plasma prolactin (PRL) concentrations are generally high during post-hatch parental care in birds, and may be a candidate mechanism that regulates variation in parental care and other reproductive success outcomes. Here we analyze the relationship between PRL, parental behavior (chick brooding and feeding) and reproductive success outcomes (clutch size, number of chicks hatched, and chick survival) for the first time in the zebra finch (Taeniopygia guttata). Birds were given cabergoline, a dopamine agonist traditionally used to lower prolactin in mammals, or vehicle in their food. Cabergoline had no effect on prolactin concentrations, but across both groups we found that PRL is positively correlated with parental behavior, number of chicks hatched, and chick survival, but not clutch size. Results from this study will inform hypotheses and predictions for future manipulation studies which test for a causal role for PRL in parental traits.
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Affiliation(s)
- Kristina O Smiley
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA.
| | - Elizabeth Adkins-Regan
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA; Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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16
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Storey AE, Ziegler TE. Primate paternal care: Interactions between biology and social experience. Horm Behav 2016; 77:260-71. [PMID: 26253726 PMCID: PMC4968077 DOI: 10.1016/j.yhbeh.2015.07.024] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 11/15/2022]
Abstract
This article is part of a Special Issue "Parental Care".We review recent research on the roles of hormones and social experiences on the development of paternal care in humans and non-human primates. Generally, lower concentrations of testosterone and higher concentrations of oxytocin are associated with greater paternal responsiveness. Hormonal changes prior to the birth appear to be important in preparation for fatherhood and changes after the birth are related to how much time fathers spend with offspring and whether they provide effective care. Prolactin may facilitate approach and the initiation of infant care, and in some biparental non-human primates, it affects body mass regulation. Glucocorticoids may be involved in coordinating reproductive and parental behavior between mates. New research involving intranasal oxytocin and neuropeptide receptor polymorphisms may help us understand individual variation in paternal responsiveness. This area of research, integrating both biological factors and the role of early and adult experience, has the potential to suggest individually designed interventions that can strengthen relationships between fathers and their partners and offspring.
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Affiliation(s)
- Anne E Storey
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X9, Canada; Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X9, Canada.
| | - Toni E Ziegler
- National Primate Research Center University of Wisconsin-Madison, Madison, WI 53715, USA
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17
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Bales KL, Saltzman W. Fathering in rodents: Neurobiological substrates and consequences for offspring. Horm Behav 2016; 77:249-59. [PMID: 26122293 PMCID: PMC4691427 DOI: 10.1016/j.yhbeh.2015.05.021] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 01/08/2023]
Abstract
This article is part of a Special Issue "Parental Care". Paternal care, though rare among mammals, is routinely displayed by several species of rodents. Here we review the neuroanatomical and hormonal bases of paternal behavior, as well as the behavioral and neuroendocrine consequences of paternal behavior for offspring. Fathering behavior is subserved by many of the same neural substrates which are also involved in maternal behavior (for example, the medial preoptic area of the hypothalamus). While gonadal hormones such as testosterone, estrogen, and progesterone, as well as hypothalamic neuropeptides such as oxytocin and vasopressin, and the pituitary hormone prolactin, are implicated in the activation of paternal behavior, there are significant gaps in our knowledge of their actions, as well as pronounced differences between species. Removal of the father in biparental species has long-lasting effects on behavior, as well as on these same neuroendocrine systems, in offspring. Finally, individual differences in paternal behavior can have similarly long-lasting, if more subtle, effects on offspring behavior. Future studies should examine similar outcome measures in multiple species, including both biparental species and closely related uniparental species. Careful phylogenetic analyses of the neuroendocrine systems presumably important to male parenting, as well as their patterns of gene expression, will also be important in establishing the next generation of hypotheses regarding the regulation of male parenting behavior.
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Affiliation(s)
- Karen L Bales
- Department of Psychology, University of California, Davis, USA; California National Primate Research Center, USA.
| | - Wendy Saltzman
- Department of Biology, University of California, Riverside, USA
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Snowdon CT, Ziegler TE. Variation in prolactin is related to variation in sexual behavior and contact affiliation. PLoS One 2015; 10:e0120650. [PMID: 25799436 PMCID: PMC4370565 DOI: 10.1371/journal.pone.0120650] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 01/26/2015] [Indexed: 11/18/2022] Open
Abstract
Prolactin is associated with both maternal and paternal care and appears important in developing a bond between parent and infant. In contrast with oxytocin, another hormone important in infant care, there is scant information on the role of prolactin in maintaining adult heterosexual relationships. We present here the first results demonstrating a relationship between prolactin levels and sexual and contact affiliation behavior in a pair-bonded species. We studied cotton-top tamarins, a socially-monogamous, cooperatively-breeding primate. We measured chronic urinary prolactin levels over a four week period to include the entire female ovulatory cycle and correlated prolactin levels in males and females with simultaneous measures of contact affiliation and sexual behavior. Current mothers who were no longer nursing displayed lower amounts of sexual behavior and proximity than non-breeding females and also had marginally lower levels of prolactin. The prolactin levels of males and females were similar within pairs, and variation in prolactin levels for both sexes was explained both by the amount of sexual behavior and contact affiliation. The results parallel a previous study that compared oxytocin levels with sociosexual behavior in the same species, and supports the hypothesis that both prolactin and oxytocin are involved in pair-bonding as well as in infant care.
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Affiliation(s)
- Charles T Snowdon
- Department of Psychology, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
| | - Toni E Ziegler
- Wisconsin National Primate Research Center, Madison, Wisconsin, United States of America
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Saltzman W, Ziegler TE. Functional significance of hormonal changes in mammalian fathers. J Neuroendocrinol 2014; 26:685-96. [PMID: 25039657 PMCID: PMC4995091 DOI: 10.1111/jne.12176] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 12/25/2022]
Abstract
In the 5-10% of mammals in which both parents routinely provide infant care, fathers as well as mothers undergo systematic endocrine changes as they transition into parenthood. Although fatherhood-associated changes in such hormones and neuropeptides as prolactin, testosterone, glucocorticoids, vasopressin and oxytocin have been characterised in only a small number of biparental rodents and primates, they appear to be more variable than corresponding changes in mothers, and experimental studies typically have not provided strong or consistent evidence that these endocrine shifts play causal roles in the activation of paternal care. Consequently, their functional significance remains unclear. We propose that endocrine changes in mammalian fathers may enable males to meet the species-specific demands of fatherhood by influencing diverse aspects of their behaviour and physiology, similar to many effects of hormones and neuropeptides in mothers. We review the evidence for such effects, focusing on recent studies investigating whether mammalian fathers in biparental species undergo systematic changes in (i) energetics and body composition; (ii) neural plasticity, cognition and sensory physiology; and (iii) stress responsiveness and emotionality, all of which may be mediated by endocrine changes. The few published studies, based on a small number of rodent and primate species, suggest that hormonal and neuropeptide alterations in mammalian fathers might mediate shifts in paternal energy balance, body composition and neural plasticity, although they do not appear to have major effects on stress responsiveness or emotionality. Further research is needed on a wider variety of biparental mammals, under more naturalistic conditions, to more fully determine the functional significance of hormone and neuropeptide profiles of mammalian fatherhood and to clarify how fatherhood may trade off with (or perhaps enhance) aspects of organismal function in biparental mammals.
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Affiliation(s)
- Wendy Saltzman
- Department of Biology, University of California, Riverside
| | - Toni E. Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin – Madison
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Prolactin Receptor Gene Diversity in Azara’s Owl Monkeys (Aotus azarai) and Humans (Homo sapiens) Suggests a Non-Neutral Evolutionary History among Primates. INT J PRIMATOL 2013. [DOI: 10.1007/s10764-013-9721-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Zysling DA, Park SU, McMillan EL, Place NJ. Photoperiod-gonadotropin mismatches induced by treatment with acyline or FSH in Siberian hamsters: impacts on ovarian structure and function. Reproduction 2012; 144:603-16. [PMID: 22936286 DOI: 10.1530/rep-12-0155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Many seasonal breeders time their reproductive efforts to specific times of the year to ensure adequate resources for the production and care of young. For long-day (LD) breeders, females born before the summer solstice (LDs) reach sexual maturity quickly and often breed that same year, whereas females born after the summer solstice (short days (SDs)) may delay reproductive development to the following spring when environmental conditions are favorable for reproduction. In Siberian hamsters, development in SD is associated with structural and functional differences in the ovary compared with females held in LD, including a greater number of primordial follicles and an abundance of hypertrophied granulosa cells (HGCs), which are immunoreactive for anti-Müllerian hormone. The goal of this study was to determine whether SD-induced gonadotropin suppression is responsible for these phenotypic differences. Gonadotropin levels were suppressed in LD hamsters using the GNRH antagonist acyline. Conversely, to determine whether the SD ovarian phenotype is completely reversed by gonadotropin stimulation, recombinant human FSH (rhFSH) was administered. Our treatments were successful in mimicking FSH concentrations of the opposite photoperiod, but they did not produce a comparable change in the ovarian phenotype. Most notable was the lack of HGCs in the ovaries of acyline-treated LD females. Similarly, HGCs were maintained in the ovaries of SD females treated with rhFSH. Our data suggest that gonadotropins alone do not account for the SD ovarian phenotype. Future studies will determine whether SD-induced changes in other factors underlie these phenotypic changes.
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Affiliation(s)
- D A Zysling
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, S2-072 Schurman Hall, Ithaca, New York 14853, USA.
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22
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Gettler LT, McDade TW, Feranil AB, Kuzawa CW. Prolactin, fatherhood, and reproductive behavior in human males. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2012; 148:362-70. [DOI: 10.1002/ajpa.22058] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 02/20/2012] [Indexed: 11/10/2022]
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Storey AE, Noseworthy DE, Delahunty KM, Halfyard SJ, McKay DW. The effects of social context on the hormonal and behavioral responsiveness of human fathers. Horm Behav 2011; 60:353-61. [PMID: 21767539 DOI: 10.1016/j.yhbeh.2011.07.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/21/2011] [Accepted: 07/01/2011] [Indexed: 11/25/2022]
Abstract
We tested first-time fathers with their 22-month old toddlers to determine whether social context variables such as pre-test absence from the child and presence of the mother affected physiological measures associated with paternal responsiveness. Heart rate and blood pressure readings as well as blood samples to determine prolactin, testosterone and cortisol levels were taken before and after the 30-min father-toddler interactions. Fathers were tested on a day when they were away from their child for several hours before testing ('without-child' day) and on another day where they remained with their child throughout the day ('with-child' day). Most measures decreased over the 30-min test period but relative decreases were context-dependent. Men maintained higher prolactin levels when they were away from their children longer before testing on the 'without-child' day. Cortisol levels decreased during both tests and they decreased more on the 'with-child' day for men who had spent more time alone with their toddler before the test. Heart-rate and diastolic (but not systolic) blood pressure decreased more on the 'with-child' day than on the 'without-child' day. Fathers' testosterone levels decreased when their partners were less involved in the interactions. Compared to men with high responsiveness ratings on both days, men whose responsiveness increased after being away from their child on the 'without-child' day maintained higher systolic blood pressure and had a greater decrease in testosterone levels. We conclude that context may be more important in determining fathers' physiological responses to child contact than has previously been appreciated, particularly for some individuals.
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Affiliation(s)
- Anne E Storey
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
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24
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Storey A, Walsh C. How Fathers Evolve: A Functional Analysis of Fathering Behavior. NATIONAL SYMPOSIUM ON FAMILY ISSUES 2011. [DOI: 10.1007/978-1-4419-7361-0_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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25
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Early fitness consequences and hormonal correlates of parental behaviour in the social rodent, Octodon degus. Physiol Behav 2010; 101:509-17. [DOI: 10.1016/j.physbeh.2010.07.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 07/10/2010] [Accepted: 07/27/2010] [Indexed: 11/18/2022]
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26
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Ziegler TE, Prudom SL, Zahed SR, Parlow AF, Wegner F. Prolactin's mediative role in male parenting in parentally experienced marmosets (Callithrix jacchus). Horm Behav 2009; 56:436-43. [PMID: 19664636 PMCID: PMC2761515 DOI: 10.1016/j.yhbeh.2009.07.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/24/2009] [Accepted: 07/29/2009] [Indexed: 11/19/2022]
Abstract
Prolactin has been implicated in promoting paternal care behaviors but little evidence of causality has been found to date except for birds and fish. This study was designed to examine the possible causal relationships between prolactin and male parenting behaviors, reproductive hormones, and physical changes in cooperatively breeding common marmosets, Callithrix jacchus. Fifteen parentally experienced fathers were studied over three consecutive infant care periods during two weeks prior and three weeks following their mates' parturition under three-treatment conditions: normal control pregnancy, decreased prolactin and elevated prolactin. The treatments significantly altered the serum prolactin levels in the fathers. Using three methods of determining a father's level of parental care: infant carrying, family effort and responsiveness to infant stimulus tests, we found that only the male response to infant stimuli was altered by the hormone treatments. Lowering prolactin significantly reduced male responsiveness to infant stimuli but elevating prolactin showed the same effect. Hormonal sampling indicated that testosterone levels showed an inverse relationship to prolactin levels during a normal peripartum period and prolactin treatment reduced this relationship. Prepartum estradiol levels were significantly elevated during the lowered prolactin treatment and estradiol was significantly lowered postpartum with the elevated prolactin treatment. Father's weight decreased significantly by the third week of infant care during the normal treatment. Males in the elevated prolactin treatment lost little or no weight from prepartum while in the lowered prolactin treatment showed the most weight loss. The present findings did not distinguish a direct causal relationship of prolactin on behavior in experienced fathers but did find an interaction with other hormones and weight gain.
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Affiliation(s)
- Toni E Ziegler
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715, USA.
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27
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Kentner AC, Abizaid A, Bielajew C. Modeling dad: animal models of paternal behavior. Neurosci Biobehav Rev 2009; 34:438-51. [PMID: 19744516 DOI: 10.1016/j.neubiorev.2009.08.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 08/31/2009] [Accepted: 08/31/2009] [Indexed: 01/02/2023]
Abstract
In humans, paternal behaviors have a strong influence on the emotional and social development of children. Fathers, more frequently than mothers, leave the family nucleus, and/or become abusive, leading to offspring that are more likely to grow under stressful conditions and greater susceptibility to abnormal health and social outcomes. Literature on parental behaviors, human or animal, has primarily focused on the interactions between mothers and offspring, with little research directed at understanding paternal behavior. In animal studies, experimenters correlate paternal behaviors with those seen in rodent or primate mothers, often under situations in which behaviors such as nest protection, huddling, pup grooming, and retrieval are artificially induced. In humans, the majority of the studies have looked at paralleling hormonal changes in fathers with those occurring in mothers, or observed paternal behaviors in populations with specific anthropological backgrounds. These studies reveal commonalities in parental behaviors and their underlying neural circuits. However, this work highlights the possibility that paternal behavior has components that are strictly masculine with unique neurobiological mechanisms. This review summarizes this information and provides a current view of a topic that needs further exploration.
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Affiliation(s)
- Amanda C Kentner
- Hotckiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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28
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Schradin C. Differences in prolactin levels between three alternative male reproductive tactics in striped mice (Rhabdomys pumilio). Proc Biol Sci 2008; 275:1047-52. [PMID: 18230588 DOI: 10.1098/rspb.2008.0004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In male fishes, birds and mammals, increased prolactin secretion is thought to play a role in species showing paternal behaviours. This hypothesis was investigated in the striped mouse (Rhabdomys pumilio). This paper compares serum prolactin levels in 71 free-living male striped mice following three different reproductive tactics: (i) paternal group-living breeders, (ii) alloparental philopatric group-living males, and (iii) roaming non-paternal solitary males. Prolactin levels of breeding males were significantly higher than that of roamers. Alloparental philopatric males had low prolactin levels, which concur with studies of cooperatively breeding mammals, but contrasts with studies of cooperatively breeding birds. Both breeding males and females showed a decrease in prolactin levels after the breeding season, but not alloparental philopatric males. Prolactin levels were correlated with neither corticosterone levels nor age. These results are in agreement with the hypothesis that prolactin is one proximate mechanism of male reproductive tactics, possibly regulating differences in male parental care.
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Affiliation(s)
- Carsten Schradin
- Department of Animal Behavior, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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29
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Schradin C. Comments to K.E. Wynne-Edwards and M.E. Timonin 2007. Paternal care in rodents: Weakening support of hormonal regulation of the transition to behavioral fatherhood in rodent animal models of biparental care, Horm & Behav 52: 114-121. Horm Behav 2007; 52:557-9; author reply 560. [PMID: 17904140 DOI: 10.1016/j.yhbeh.2007.08.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 08/07/2007] [Accepted: 08/08/2007] [Indexed: 11/29/2022]
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30
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Wynne-Edwards KE, Timonin ME. Paternal care in rodents: weakening support for hormonal regulation of the transition to behavioral fatherhood in rodent animal models of biparental care. Horm Behav 2007; 52:114-21. [PMID: 17482188 DOI: 10.1016/j.yhbeh.2007.03.018] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 03/27/2007] [Accepted: 03/28/2007] [Indexed: 11/26/2022]
Abstract
Male rodents that are naturally paternal, like all females, must inhibit infanticide and activate direct parental behavior as they become parents. Males, however, alter their behavior in the absence of parturition, postpartum ovulation and lactation, and therefore do not experience the hormone dynamics associated with such conditions. Paternal males might nevertheless use the same hormones to activate pre-existing maternal behavior pathways in the brain. Positive and inverse associations between prolactin, sex steroids (estradiol, testosterone, progesterone), glucocorticoids, oxytocin and vasopressin and paternal behavior are reviewed. Across biparental rodents (Phodopus campbelli, Peromyscus californicus, Microtus ochrogaster, and Meriones unguiculatus), as well as non-human primates and men, hormone-behavior associations are broadly supported. However, experimental manipulations (largely restricted to P. campbelli) suggest that the co-variation of hormones and paternal behavior is not causal in paternal behavior. Perhaps the hormone-behavior associations shared by P. campbelli and other paternal males are important for other challenges at the same time as fatherhood (e.g., mating during the postpartum estrus). On the other hand, each paternal species might, instead, have unique neuroendocrine pathways to parental behavior. In the latter case, future comparisons might reveal extraordinary plasticity in how the brain forms social bonds and alters behavior in family groups.
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31
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Delahunty KM, McKay DW, Noseworthy DE, Storey AE. Prolactin responses to infant cues in men and women: effects of parental experience and recent infant contact. Horm Behav 2007; 51:213-20. [PMID: 17150219 DOI: 10.1016/j.yhbeh.2006.10.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 10/16/2006] [Accepted: 10/16/2006] [Indexed: 11/23/2022]
Abstract
We used a longitudinal design to test whether parental experience differentially affects the development of prolactin responses to infant cues in men and women. Couples provided two blood samples at three tests, one test just before their babies were born, and two tests during the early postnatal period (n=21). Nine couples repeated the tests near the birth of their second babies. In the 30 min between the two samples, couples listened to recorded infant cries at the prenatal test and held their baby (fathers) or a doll (mothers) at the postnatal tests. Blood samples were analyzed for prolactin concentrations. Prolactin values were then related to sex and parity differences as well as to questionnaire data concerning emotional responses to infant cries and previous infant contact. We found that (1) prior to the birth of both the first and second babies, women's prolactin concentrations increased after exposure to infant stimuli, whereas men's prolactin concentrations decreased; postnatal sex differences varied with parity; (2) women's prolactin reactivity did not change significantly with parental experience; (3) the same men's prolactin concentrations decreased after holding their first newborns but increased after holding their second newborns; this change was not gradual or permanent; (4) men reporting concern after hearing recorded infant cries showed a different postnatal pattern of prolactin change after holding their babies than men not reporting concern; and (5) men who had little contact with their babies just prior to testing had a more positive prolactin response than men who had recently held their babies for longer periods. Although parental experience appears to affect men's prolactin responses, differences in reactivity were also related to patterns of recent infant contact and individual differences in responses to infant cues.
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Affiliation(s)
- Krista M Delahunty
- Cognitive and Behavioural Ecology Graduate Programme, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
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32
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Timonin ME, Place NJ, Wanderi E, Wynne-Edwards KE. Phodopus campbelli detect reduced photoperiod during development but, unlike Phodopus sungorus, retain functional reproductive physiology. Reproduction 2006; 132:661-70. [PMID: 17008477 DOI: 10.1530/rep.1.00019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Golden (Mesocricetus auratus) and Siberian (Phodopus sungorus) hamsters are widely used as animal models for seasonal reproduction; butM. auratusshows no developmental delay in short days until after sexual maturity, whereasP. sungorusjuveniles delay development in short days. As the photoperiodic response ofPhodopus campbelliis not well established, litters of the twoPhodopusspecies were gestated and reared under long days (14 h light:10 h darkness) or short days (10 h light:14 h darkness) until 70 days of age. As expected, under short photoperiodP. sungorusshowed reduced body, testes, epididymides, uterus, and ovary weight; antral follicles and corpora lutea were absent and vaginae remained closed. Animals moulted to winter pelage, and low concentrations of each of leptin, testosterone, and prolactin were present in male serum.Phodopus campbellijuveniles also responded to the short photoperiod as measured by reduced body, testes, epididymides, and ovary weight. The summer pelage persisted. However, both sexes ofP. campbellideveloped functional reproduction under 10 h light:14 h darkness. All females had a patent vagina by 10 weeks; ovaries contained antral follicles and corpora lutea, and uteri were not reduced in weight. In males, the concentrations of testosterone, leptin, and prolactin were not reduced by short photoperiod. Developmental patterns in the three species of hamster, therefore, differ and are not predicted by relatedness or latitude of origin. Other ecological traits, such as predictability of summer rainfall, ambient temperature, and differential responses to social cues might be important.
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Affiliation(s)
- Mary E Timonin
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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33
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Guimont FS, Wynne-Edwards KE. Individual variation in cortisol responses to acute "on-back" restraint in an outbred hamster. Horm Behav 2006; 50:252-60. [PMID: 16697381 DOI: 10.1016/j.yhbeh.2006.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 03/03/2006] [Accepted: 03/17/2006] [Indexed: 10/24/2022]
Abstract
An outbred species of dwarf hamster (Phodopus campbelli) was used to assess between-individual variability in the response to, and recovery from, a one-time stressor of 6 min of physical restraint in a subordinate, on-back, position. Four repeated plasma samples were drawn under home-cage isoflurane anesthesia from 33 males and 38 females 50 min before, and then 10, 60, and 120 min after the stress onset. Plasma cortisol concentrations were higher in females than males, but there was no evidence for a sex difference in response to the stressor. The expected cross-sectional increase ( approximately 50 ng/ml) in response to the stressor, followed by recovery, was seen. However, there was extensive individual variation, ranging from no reaction to continuous decline from the initial to the final sample. Results were expressed in four ways (absolute concentration, relative concentration, and area under the curve relative to ground and relative to the stress-induced increase) and also standardized and subjected to hierarchical cluster analysis. Clusters failed to effectively partition the between-individual variation and did not cluster by sex, age, or housing conditions. The current study cautions against ignoring individual differences and suggests that outbred animal models might be particularly relevant to understanding stress-related pathological conditions.
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Affiliation(s)
- François S Guimont
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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34
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Almond REA, Brown GR, Keverne EB. Suppression of prolactin does not reduce infant care by parentally experienced male common marmosets (Callithrix jacchus). Horm Behav 2006; 49:673-80. [PMID: 16480723 DOI: 10.1016/j.yhbeh.2005.12.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 12/06/2005] [Accepted: 12/08/2005] [Indexed: 01/23/2023]
Abstract
High levels of prolactin have been found to correlate with the expression of paternal care in a variety of taxa. However, in mammals, there is little experimental evidence that prolactin is causally involved in the stimulation or maintenance of paternal care. Here, we suppressed prolactin production in paternally experienced common marmoset fathers in their family groups during the first 2 weeks after their infants were born. Circulating prolactin levels were suppressed using cabergoline (Dostinex: Pfizer), a long acting dopamine (D2) agonist with minimal behavioural side-effects. A within-subject design was used to compare behavioural and hormonal data on 5 paternally experienced fathers during two consecutive births. Cabergoline reduced prolactin to negligible levels in all fathers without effecting testosterone, DHT and cortisol and without adverse side-effects. However, lowering prolactin had no significant effect on the expression of majority of the behaviour patterns associated with paternal care. These included infant carrying, infant grooming and the frequency with which fathers retrieved and rejected infants. The only infant-related behaviour to be affected was the frequency with which fathers touched, licked and investigated infants. We noted a marginally significant increase in this behaviour during cabergoline treatment. Despite the lack of effect on paternal care, cabergoline did exert an effect on the affiliative/sexual behaviour of fathers as there was a significant increase in the grooming behaviour fathers directed at and received from their mates during drug treatment. This study showed that experienced male marmosets can express paternal behaviour in the absence of the high prolactin levels normally seen after infants are born.
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Affiliation(s)
- Rosamunde E A Almond
- Department of Psychology, University of Wisconsin, 1202 West Johnson Street, Madison, WI 53706, USA.
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35
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Hume JM, Wynne-Edwards KE. Paternal responsiveness in biparental dwarf hamsters (Phodopus campbelli) does not require estradiol. Horm Behav 2006; 49:538-44. [PMID: 16458311 DOI: 10.1016/j.yhbeh.2005.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 11/24/2005] [Accepted: 11/25/2005] [Indexed: 11/25/2022]
Abstract
Males of the biparental hamster species Phodopus campbelli act as midwives and are responsive to an experimentally displaced pup. Males also have peripheral estradiol concentrations that are similar to conspecific females. Castration reduces peripheral estradiol, yet does not affect paternal responsiveness despite the known role of estradiol in maternal behavior. Synthesis of estradiol within the central nervous system, however, might not be affected by castration. Males received implants of osmotic pumps containing the aromatase inhibitor letrozole to reduce both peripheral and central estradiol concentrations. Though estradiol was effectively reduced, it had no effect on paternal responsiveness or reproductive success. Neither testosterone nor aggression directed towards an intruder was altered. Results support the emerging conclusion that estradiol is not required for the exceptional paternal behavior of male P. campbelli.
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Affiliation(s)
- Johanna M Hume
- Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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36
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Gregg JK, Wynne-Edwards KE. In uniparentalPhodopus sungorus, new mothers, and fathers present during the birth of their offspring, are the only hamsters that readily consume fresh placenta. Dev Psychobiol 2006; 48:528-36. [PMID: 17016837 DOI: 10.1002/dev.20174] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Placentophagia is common among parturient female mammals but non-parturient females generally refuse placenta. Biparental male dwarf hamsters (Phodopus campbelli) readily consume placenta. The present study quantified placentophagia and liver acceptance in the closely related Siberian hamster P. sungorus in which males do not participate in the birth and are not responsive to a displaced pup. Sexually naïve P. sungorus males and females refused both placenta and liver (all groups <10%). Reproductive females specifically consumed placenta on the day before (G17), and the day of, parturition (G18) (>80%). Males rejected both tissues on G17 and accepted placenta soon after the birth (G18) (80%) only if they were present during the birth. Palatability of the placenta was not responsible for the species difference as P. campbelli accepted P. sungorus placenta. Results are consistent with a neophobic reaction to both placenta (conspecific or heterospecific) and liver as P. sungorus also rejected P. campbelli placenta.
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Affiliation(s)
- Jennifer K Gregg
- Department of Biology, Queen's University Kingston, Ontario K7L 3N6 Canada
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Hume JM, Wynne-Edwards KE. Castration reduces male testosterone, estradiol, and territorial aggression, but not paternal behavior in biparental dwarf hamsters (Phodopus campbelli). Horm Behav 2005; 48:303-10. [PMID: 15925370 DOI: 10.1016/j.yhbeh.2005.04.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 04/03/2005] [Accepted: 04/04/2005] [Indexed: 10/25/2022]
Abstract
Biparental male hamsters, Phodopus campbelli, act as midwives during the birth of their litter and are highly responsive to an experimentally displaced pup. They also have high peripheral concentrations of estradiol, a hormone with known roles in maternal behavior. Surgical castration during the gestation of their first litter was used to investigate the source of that estradiol and the functional role of testicular sex steroids in paternal responsiveness. In Experiment I, castration reduced both testosterone and estradiol concentrations, confirming that the testes were the primary source of estradiol. However, neither paternal responsiveness nor multiple measures of reproductive success were altered by the castration. Aggression directed towards an intruder, however, was reduced by castration. In Experiment II, removal of prior experience with birth or pups also failed to alter paternal responsiveness in castrated males. Although the present results do not preclude a role for local estradiol synthesis in the brain, results do not support an association between high circulating estradiol in males and their paternal behavior.
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Affiliation(s)
- Johanna M Hume
- Department of Biology, Queen's University, Kingston, Ontario, Canada.
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Ma E, Lau J, Grattan DR, Lovejoy DA, Wynne-Edwards KE. Male and female prolactin receptor mRNA expression in the brain of a biparental and a uniparental hamster, phodopus, before and after the birth of a litter. J Neuroendocrinol 2005; 17:81-90. [PMID: 15796758 DOI: 10.1111/j.1365-2826.2005.01278.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prolactin receptor (PRL-R) mRNA transcript level was quantified in the choroid plexus (ChP) of a naturally biparental hamster, Phodopus campbelli, and its otherwise similar, yet nonpaternal, sibling species, Phodopus sungorus. Pair-housed males and females on the day before the birth of their first litter (G17), the day after birth (L1), lactation day 5 (L5), and unpaired animals that were sexually naïve, were tested. PRL-R mRNA transcript level relative to total RNA, was evaluated by reverse transcriptase-polymerase chain reaction using primers common to the long- and short-form of the PRL-R in Phodopus. In the ChP, a region implicated in prolactin transport into the central nervous system, females had the expected increase in PRL-R mRNA transcript from dioestrus to L5, consistent with known actions of prolactin. As predicted, males and females of the biparental species were similar, although PRL-R mRNA in naive males was higher than in dioestrus females. Males of the two species also differed as predicted. PRL-R mRNA transcript levels were higher in the biparental males. In addition, P. campbelli males had low PRL-R mRNA at G17 compared to L5. By contrast, non-paternal P. sungorus males had elevated PRL-R mRNA transcript levels on G17 relative to unpaired males. We conclude that PRL-R mRNA in the ChP is differentially regulated before and after birth in a paternal and a nonpaternal male.
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Affiliation(s)
- E Ma
- Department of Biology, Queen's University, Kingston, Canada
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