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Matas D, Doniger T, Sarid S, Asfur M, Yadid G, Khokhlova IS, Krasnov BR, Kam M, Degen AA, Koren L. Sex differences in testosterone reactivity and sensitivity in a non-model gerbil. Gen Comp Endocrinol 2020; 291:113418. [PMID: 32027878 DOI: 10.1016/j.ygcen.2020.113418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/28/2020] [Accepted: 02/01/2020] [Indexed: 11/28/2022]
Abstract
Although testosterone (T) is a key regulator in vertebrate development, physiology, and behaviour in both sexes, studies suggest that its regulation may be sex-specific. We measured circulating T levels in Baluchistan gerbils (Gerbillus nanus) in the field and in the lab all year round and found no significant sex differences. However, we observed sex differences in circulating T levels following gonadotropin-releasing hormone (GnRH) challenge and T implants in this non-model species. Whereas only males elevated T following a GnRH challenge, females had higher serum T concentrations following T implant insertion. These differences may be a result of different points of regulation along the hypothalamic-pituitary-gonadal (HPG) axis. Consequently, we examined sex differences in the mRNA expression of the androgen receptor (AR) in multiple brain regions. We identified AR and β-actin sequences in assembled genomic sequences of members of the Gerbillinae, which were analogous to rat sequences, and designed primers for them. The distribution of the AR in G. nanus brain regions was similar to documented expression profiles in rodents. We found lower AR mRNA levels in females in the striatum. Additionally, G. nanus that experienced housing in mixed-sex pairs had higher adrenal AR expression than G. nanus that were housed alone. Regulation of the gerbil HPG axis may reflect evolutionary sex differences in life-history strategies, with males ready to reproduce when receptive females are available, while the possible reproductive costs associated with female T direct its regulation upstream.
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Affiliation(s)
- Devorah Matas
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Tirza Doniger
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Shani Sarid
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Mustafa Asfur
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Gal Yadid
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel; The Leslie and Susan Gonda (Goldschmidt) Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
| | - Irina S Khokhlova
- Desert Animal Adaptations and Husbandry, Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000 Midreshet Ben-Gurion, Israel
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, Swiss Institute of Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000 Midreshet Ben-Gurion, Israel
| | - Michael Kam
- Desert Animal Adaptations and Husbandry, Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000 Midreshet Ben-Gurion, Israel
| | - A Allan Degen
- Desert Animal Adaptations and Husbandry, Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000 Midreshet Ben-Gurion, Israel
| | - Lee Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
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Schlinger BA, Paul K, Monks DA. Muscle, a conduit to brain for hormonal control of behavior. Horm Behav 2018; 105:58-65. [PMID: 30040953 DOI: 10.1016/j.yhbeh.2018.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 12/13/2022]
Abstract
SBN Elsevier Lecture Investigation into mechanisms whereby hormones control behavior often starts with actions on central nervous system (CNS) motivation and motor systems and is followed by assessment of CNS drive of coordinated striated muscle contractions. Here we turn this perspective on its head by discussing ways in which hormones might first act on muscle that then secondarily drive upstream the evolution and function of the CNS. While there is a lengthy history for consideration of this perspective, newly discovered properties of muscle signaling reveal novel mechanisms that may well be captured by endocrine systems and thus of interest to behavioral endocrinologists.
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Affiliation(s)
- Barney A Schlinger
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States of America; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, United States of America; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, United States of America; Smithsonian Tropical Research Institute, Panama City, Panama.
| | - Ketema Paul
- Department of Integrative Biology and Physiology, University of California, Los Angeles, United States of America; Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, United States of America
| | - D Ashley Monks
- Department of Psychology, University of Toronto Mississauga, Canada; Cell and Systems Biology, University of Toronto, Canada
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3
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Forger NG, Ruszkowski E, Jacobs A, Wallen K. Effects of sex and prenatal androgen manipulations on Onuf's nucleus of rhesus macaques. Horm Behav 2018; 100:39-46. [PMID: 29510099 PMCID: PMC6084473 DOI: 10.1016/j.yhbeh.2018.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/15/2018] [Accepted: 03/02/2018] [Indexed: 10/17/2022]
Abstract
The role of gonadal steroids in sexual differentiation of the central nervous system (CNS) is well established in rodents, but no study to date has manipulated androgens prenatally and examined their effects on any CNS structure in a primate. Onuf's nucleus is a column of motoneurons in the sacral spinal cord that innervates the striated perineal muscles. This cell group is larger in males than in females of many species, due to androgens acting during a sensitive perinatal period. Here, we examined Onuf's nucleus in 21 adult rhesus monkeys, including control males and females, as well as males whose mothers had been treated with an anti-androgen or testosterone during gestation. We found a robust sex difference, with more motoneurons in control males than in females. The soma size of Onuf's nucleus motoneurons was also marginally larger in males. Treatment with the anti-androgen flutamide for 35-40 days during early gestation partially blocked masculinization of Onuf's nucleus: motoneuron number in flutamide-treated males was decreased relative to control and testosterone-treated males, but remained greater than in females, with no effect on cell size. A control motor nucleus that innervates foot muscles (Pes9) showed no difference in motoneuron number or size between control males and females. Prenatal testosterone treatment of males did not alter Onuf's nucleus motoneuron number, but did increase the size of both Onuf's and Pes9 motoneurons. Thus, prenatal androgen manipulations cause cellular-level changes in the primate CNS, which may underlie previously observed effects of these manipulations on behavior.
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Affiliation(s)
- Nancy G Forger
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
| | - Elara Ruszkowski
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Andrew Jacobs
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Kim Wallen
- Department of Psychology, Emory University, Atlanta, GA 30322, United States
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Fusani L, Barske J, Day LD, Fuxjager MJ, Schlinger BA. Physiological control of elaborate male courtship: female choice for neuromuscular systems. Neurosci Biobehav Rev 2014; 46 Pt 4:534-46. [PMID: 25086380 DOI: 10.1016/j.neubiorev.2014.07.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 07/14/2014] [Accepted: 07/22/2014] [Indexed: 12/19/2022]
Abstract
Males of many animal species perform specialized courtship behaviours to gain copulations with females. Identifying physiological and anatomical specializations underlying performance of these behaviours helps clarify mechanisms through which sexual selection promotes the evolution of elaborate courtship. Our knowledge about neuromuscular specializations that support elaborate displays is limited to a few model species. In this review, we focus on the physiological control of the courtship of a tropical bird, the golden-collared manakin, which has been the focus of our research for nearly 20 years. Male manakins perform physically elaborate courtship displays that are quick, accurate and powerful. Females seem to choose males based on their motor skills suggesting that neuromuscular specializations possessed by these males are driven by female choice. Male courtship is activated by androgens and androgen receptors are expressed in qualitatively and quantitatively unconventional ways in manakin brain, spinal cord and skeletal muscles. We propose that in some species, females select males based on their neuromuscular capabilities and acquired skills and that elaborate steroid-dependent courtship displays evolve to signal these traits.
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Affiliation(s)
- Leonida Fusani
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy.
| | - Julia Barske
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Lainy D Day
- Department of Biology, University of Mississippi, University, MS 38677, USA.
| | - Matthew J Fuxjager
- Department of Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Barney A Schlinger
- Department of Integrative Biology and Physiology, Laboratory of Neuroendocrinology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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Williams B, Northcutt KV, Rusanowsky RD, Mennella TA, Lonstein JS, Quadros-Mennella PS. Progesterone receptor expression in the brain of the socially monogamous and paternal male prairie vole. Brain Res 2013; 1499:12-20. [PMID: 23318255 DOI: 10.1016/j.brainres.2013.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 01/04/2013] [Accepted: 01/05/2013] [Indexed: 11/28/2022]
Abstract
Differences in the social organization and behavior of male mammals are attributable to species differences in neurochemistry, including differential expression of steroid hormone receptors. However, the distribution of progestin receptors (PR) in a socially monogamous and spontaneously parental male rodent has never been examined. Here we determined if PR exists and is regulated by testicular hormones in forebrain sites traditionally influencing socioreproductive behaviors in male prairie voles (Microtus ochrogaster). We hypothesized that PR expression in male prairie voles would differ from that described in other male rodents because PR activity inhibits parental behaviors and social memory in laboratory mice and rats. Adult male prairie voles received a sham surgery, were gonadectomized, or were gonadectomized and implanted with a testosterone-filled capsule. PR immunoreactivity (PRir) was measured four weeks later in areas of the hypothalamus and extended amygdala. A group of gonadally intact female prairie voles was included to reveal possible sex differences. We found considerable PRir in all sites examined. Castration reduced PRir in males' medial preoptic nucleus, anteroventral periventricular nucleus, ventromedial hypothalamus, and posterodorsal medial amygdala, and it was maintained in these sites by testosterone. This is the first study to examine PR expression in brain sites involved in socioreproductive behaviors in a socially monogamous and spontaneously paternal male rodent. Our results mostly reveal cross-species conservation in the distribution and hormone sensitivity of PR expression. Because PR interferes with aspects of sociality in other male rodents, PR may eventually be found to have different neurobiological actions in male prairie voles.
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Affiliation(s)
- Brittany Williams
- Department of Biological Sciences, 1200N Dupont Hwy, Delaware State University, Dover, DE 19901, USA
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Lansing SW, French JA, Lonstein JS. Circulating plasma testosterone during early neonatal life in the socially monogamous and biparental prairie vole (Microtus ochrogaster). Psychoneuroendocrinology 2013; 38:306-9. [PMID: 22770983 DOI: 10.1016/j.psyneuen.2012.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 11/16/2022]
Abstract
Adult male prairie voles (Microtus ochrogaster) are highly gregarious and socially monogamous, which is dissimilar to most other male rodents but reminiscent of many primates, including humans. This has resulted in prairie voles becoming a premier model in which to study the neural and hormonal basis of complex social behaviors, as well as the atypical development of these behaviors. This research is impeded by the complete lack of knowledge about the gonadal steroid environment during early development in this species. In many other animals, testicular hormones released during perinatal life permanently organize the neural substrates underlying later social behaviors in males, so knowledge about the presence or possibly even absence of testosterone in male prairie vole pups would provide important insight into their neurobehavioral development. In this study, male and female prairie vole pups were sacrificed 1, 2, 3, 4 or 5 days after birth and radioimmunoassay used to determine plasma levels of testosterone. We found that testosterone was detectable in both sexes on all days and that levels were significantly higher in males than females. Testosterone in neonatal males was sometimes as high as breeding males sampled one day after the birth of a litter. This study is the first to examine circulating testosterone in neonatal prairie voles, or any other species of Microtus, and the results indicate similarity to other rodents. This is surprising because some previous studies manipulating gonadal hormones in neonatal prairie voles have found limited effects on their neurobehavioral development, suggesting the existence of some unique, yet-to-be-revealed aspects of their neuroendocrine profile during early life.
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Affiliation(s)
- Sarah W Lansing
- Neuroscience Program, 108 Giltner Hall, Michigan State University, East Lansing, MI 48823, United States
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Fuxjager MJ, Schultz JD, Barske J, Feng NY, Fusani L, Mirzatoni A, Day LB, Hau M, Schlinger BA. Spinal motor and sensory neurons are androgen targets in an acrobatic bird. Endocrinology 2012; 153:3780-91. [PMID: 22635677 PMCID: PMC5393326 DOI: 10.1210/en.2012-1313] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sex steroids affect the motivation to court mates, but less is known about how they influence motor movements associated with courtship behavior. Steroidal control of motor function may be especially important for species in which courtship requires superior strength, stamina, and neuromuscular coordination. Here we use the golden-collared manakin (Manacus vitellinus) to examine whether the neuromuscular circuitry that controls motoric aspects of courtship activity is sensitive to androgens. Males of this tropical species attract mates by rapidly jumping among branches in a courtship arena and using their wings to produce loud wing snaps. Testosterone activates this display via the androgen receptor (AR), and past work reveals that manakins injected with radio-labeled T ((3)H-T) accumulate radioactivity in the spinal cord. Thus, we used quantitative PCR to measure AR, estrogen receptor-α (ER-α) subtype, and aromatase (AROM) mRNA in spinal cords of male and female manakins and zebra finches. Expression of AR, but not ER-α or aromatase, was higher throughout the manakin spinal cord compared with the zebra finch. Next, we tested whether AR-expressing skeletal muscles are innervated by motor and sensory neurons that also express AR. To do this, we backfilled spinal neurons by injecting fluorescent tracers into select AR-sensitive wing and leg muscles of wild caught male and female manakins. We then removed these spinal cords and measured AR expression with in situ hybridization. Both sexes showed abundant AR mRNA in the cervical and lumbosacral spinal enlargements as well as in dorsal root ganglia attached to these enlargements. Together our findings suggest that androgens act widely on peripheral motor and sensory circuits in golden-collared manakins to influence wing snapping displays.
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Affiliation(s)
- Matthew J Fuxjager
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, California 90095-7239, USA
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