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Stewart C, Marshall CJ. Seasonality of prolactin in birds and mammals. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:919-938. [PMID: 35686456 PMCID: PMC9796654 DOI: 10.1002/jez.2634] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/21/2022] [Accepted: 05/23/2022] [Indexed: 01/07/2023]
Abstract
In most animals, annual rhythms in environmental cues and internal programs regulate seasonal physiology and behavior. Prolactin, an evolutionarily ancient hormone, serves as a molecular correlate of seasonal timing in most species. Prolactin is highly pleiotropic with a wide variety of well-documented physiological effects; in a seasonal context prolactin is known to regulate annual changes in pelage and molt. While short-term homeostatic variation of prolactin secretion is under the control of the hypothalamus, long-term seasonal rhythms of prolactin are programmed by endogenous timers that reside in the pituitary gland. The molecular basis of these rhythms is generally understood to be melatonin dependent in mammals. Prolactin rhythmicity persists for several years in many species, in the absence of hypothalamic signaling. Such evidence in mammals has supported the hypothesis that seasonal rhythms in prolactin derive from an endogenous timer within the pituitary gland that is entrained by external photoperiod. In this review, we describe the conserved nature of prolactin signaling in birds and mammals and highlight its role in regulating multiple diverse physiological systems. The review will cover the current understanding of the molecular control of prolactin seasonality and propose a mechanism by which long-term rhythms may be generated in amniotes.
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Affiliation(s)
- Calum Stewart
- Institute of Biodiversity, Animal Health & Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Christopher J. Marshall
- Institute of Biodiversity, Animal Health & Comparative MedicineUniversity of GlasgowGlasgowUK
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2
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Ho JM, Bergeon Burns CM, Rendon NM, Rosvall KA, Bradshaw HB, Ketterson ED, Demas GE. Lipid signaling and fat storage in the dark-eyed junco. Gen Comp Endocrinol 2017; 247:166-173. [PMID: 28161439 PMCID: PMC5410188 DOI: 10.1016/j.ygcen.2017.01.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 12/13/2016] [Accepted: 01/28/2017] [Indexed: 12/11/2022]
Abstract
Seasonal hyperphagia and fattening promote survivorship in migratory and wintering birds, but reduced adiposity may be more advantageous during the breeding season. Factors such as photoperiod, temperature, and food predictability are known environmental determinants of fat storage, but the underlying neuroendocrine mechanisms are less clear. Endocannabinoids and other lipid signaling molecules regulate multiple aspects of energy balance including appetite and lipid metabolism. However, these functions have been established primarily in mammals; thus the role of lipid signals in avian fat storage remains largely undefined. Here we examined relationships between endocannabinoid signaling and individual variation in fat storage in captive white-winged juncos (Junco hyemalis aikeni) following a transition to long-day photoperiods. We report that levels of the endocannabinoid 2-arachidonoylglycerol (2-AG), but not anandamide (AEA), in furcular and abdominal fat depots correlate negatively with fat mass. Hindbrain mRNA expression of CB1 endocannabinoid receptors also correlates negatively with levels of fat, demonstrating that fatter animals experience less central and peripheral endocannabinoid signaling when in breeding condition. Concentrations of the anorexigenic lipid, oleoylethanolamide (OEA), also inversely relate to adiposity. These findings demonstrate unique and significant relationships between adiposity and lipid signaling molecules in the brain and periphery, thereby suggesting a potential role for lipid signals in mediating adaptive levels of fat storage.
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Affiliation(s)
- Jacqueline M Ho
- Department of Biology, Indiana University, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
| | - Christine M Bergeon Burns
- Department of Biology, Indiana University, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
| | - Nikki M Rendon
- Department of Biology, Indiana University, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
| | - Kimberly A Rosvall
- Department of Biology, Indiana University, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA; Program in Neuroscience, Indiana University, Bloomington, IN 47405, USA
| | - Heather B Bradshaw
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA; Program in Neuroscience, Indiana University, Bloomington, IN 47405, USA; Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Ellen D Ketterson
- Department of Biology, Indiana University, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
| | - Gregory E Demas
- Department of Biology, Indiana University, Bloomington, IN 47405, USA; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA; Program in Neuroscience, Indiana University, Bloomington, IN 47405, USA
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Gracceva G, Herde A, Groothuis TGG, Koolhaas JM, Palme R, Eccard JA. Turning Shy on a Winter's Day: Effects of Season on Personality and Stress Response inMicrotus arvalis. Ethology 2014. [DOI: 10.1111/eth.12246] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Giulia Gracceva
- Behavioural Physiology; Institute of Behavioural Neurosciences; University of Groningen; Groningen The Netherlands
- Behavioural Biology; Institute of Behavioural Neurosciences; University of Groningen; Groningen The Netherlands
| | - Antje Herde
- Department of Animal Ecology; Institute of Biochemistry and Biology; University of Potsdam; Potsdam Germany
| | - Ton G. G. Groothuis
- Behavioural Biology; Institute of Behavioural Neurosciences; University of Groningen; Groningen The Netherlands
| | - Jaap M. Koolhaas
- Behavioural Physiology; Institute of Behavioural Neurosciences; University of Groningen; Groningen The Netherlands
| | - Rupert Palme
- Institute for Medical Biochemistry; University of Veterinary Medicine; Vienna Austria
| | - Jana A. Eccard
- Department of Animal Ecology; Institute of Biochemistry and Biology; University of Potsdam; Potsdam Germany
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