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Sarid S, Naor H, Asfur M, Khokhlova IS, Krasnov BR, Kotler BP, Degen AA, Kam M, Koren L. Free-living gerbils with higher testosterone take fewer risks. Physiol Behav 2023; 269:114277. [PMID: 37352905 DOI: 10.1016/j.physbeh.2023.114277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023]
Abstract
Among the physiological differences between the sexes are circulating androgen levels. Testosterone (T) is an androgen that has been linked to aggression and risk-taking in male vertebrates, so that males with higher T are generally more aggressive and take more risks. In females, T is not often measured, and its relationship with behaviour has been less studied. The costs of elevated T are assumed to be higher for reproductive females, while the benefits higher for males. Here, we tested the association between endogenous T and risk-taking behaviours in both males and females under well-studied experimental settings in free-living Baluchistan gerbils (Gerbillus nanus; Gn). In addition, we experimentally elevated Gn T levels using implants and measured risk-taking behaviour. Surprisingly, we found that there were no differences in the association between T and risk-taking behaviours between males and females, and that in both sexes, Gn with higher T levels took fewer risks. We also found that Gn spent equal time foraging between risky (open habitat) and safe (under a bush) experimental food patches. We expected Gn, which are nocturnal, to take fewer risks during full moon nights, but found that Gn were more active during moon lit nights than during dark (new moon) nights. This study demonstrates that T has many functions, and that its effects are complex and often unpredictable. It also shows that hypotheses regarding the propensity to take risks under specific coverage and light regimes are not universal, and likely include variables such as species, environment, context, and predator-specific behavioural strategies.
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Affiliation(s)
- Shani Sarid
- Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Hen Naor
- Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Mustafa Asfur
- Faculty of Life Sciences, 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, Midreshet Ben-Gurion, Israel
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Burt P Kotler
- Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 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, 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, Midreshet Ben-Gurion, Israel
| | - Lee Koren
- Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel.
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The densities of calbindin and parvalbumin, but not calretinin neurons, are sexually dimorphic in the amygdala of the guinea pig. Brain Res 2015; 1604:84-97. [DOI: 10.1016/j.brainres.2015.01.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 01/19/2015] [Accepted: 01/28/2015] [Indexed: 11/23/2022]
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He Z, Ferguson SA, Cui L, Greenfield LJ, Paule MG. Development of the sexually dimorphic nucleus of the preoptic area and the influence of estrogen-like compounds. Neural Regen Res 2014; 8:2763-74. [PMID: 25206587 PMCID: PMC4145994 DOI: 10.3969/j.issn.1673-5374.2013.29.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 08/29/2013] [Indexed: 11/18/2022] Open
Abstract
One of the well-defined sexually dimorphic structures in the brain is the sexually dimorphic nucleus, a cluster of cells located in the preoptic area of the hypothalamus. The rodent sexually dimorphic nucleus of the preoptic area can be delineated histologically using conventional Nissl staining or immunohistochemically using calbindin D28K immunoreactivity. There is increasing use of the bindin D28K-delineated neural cluster to define the sexually dimorphic nucleus of the preoptic area in rodents. Several mechanisms are proposed to underlie the processes that contribute to the sexual dimorphism (size difference) of the sexually dimorphic nucleus of the preoptic area. Recent evidence indicates that stem cell activity, including proliferation and migration presumably from the 3rd ventricle stem cell niche, may play a critical role in the postnatal development of the sexually dimorphic nucleus of the preoptic area and its distinguishing sexually dimorphic feature: a signifi-cantly larger volume in males. Sex hormones and estrogen-like compounds can affect the size of the sexually dimorphic nucleus of the preoptic area. Despite considerable research, it remains un-clear whether estrogen-like compounds and/or sex hormones increase size of the sexually dimor-phic nucleus of the preoptic area via an increase in stem cell activity originating from the 3rd ventricle stem cell niche.
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Affiliation(s)
- Zhen He
- Division of Neurotoxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079, USA ; Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72005, USA
| | - Sherry Ann Ferguson
- Division of Neurotoxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079, USA
| | - Li Cui
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72005, USA
| | - Lazar John Greenfield
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72005, USA
| | - Merle Gale Paule
- Division of Neurotoxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079, USA
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