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Farrar VS, Flores L, Viernes RC, Ornelas Pereira L, Mushtari S, Calisi RM. Prolactin promotes parental responses and alters reproductive axis gene expression, but not courtship behaviors, in both sexes of a biparental bird. Horm Behav 2022; 144:105217. [PMID: 35785711 DOI: 10.1016/j.yhbeh.2022.105217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 05/16/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022]
Abstract
Prolactin, a hormone involved in vertebrate parental care, is hypothesized to inhibit reproductive hypothalamic-pituitary-gonadal (HPG) axis activity during parenting, thus maintaining investment in the current brood as opposed to new reproductive efforts. While prolactin underlies many parental behaviors in birds, its effects on other reproductive behaviors, such as courtship, remain unstudied. How prolactin affects neuropeptide and hormone receptor expression across the avian HPG axis also remains unknown. To address these questions, we administered ovine prolactin (oPRL) or a vehicle control to both sexes in experienced pairs of the biparental rock dove (Columba livia), after nest removal at the end of incubation. We found that oPRL promoted parental responses to novel chicks and stimulated crop growth compared to controls, consistent with other studies. However, we found that neither courtship behaviors, copulation rates nor pair maintenance differed with oPRL treatment. Across the HPG, we found oPRL had little effect on gene expression in hypothalamic nuclei, but increased expression of FSHB and hypothalamic hormone receptor genes in the pituitary. In the gonads, oPRL increased testes size and gonadotropin receptor expression, but did not affect ovarian state or small white follicle gene expression. However, the oviducts of oPRL-treated females were smaller and had lower estrogen receptor expression compared with controls. Our results highlight that some species, especially those that show multiple brooding, may continue to express mating behavior despite elevated prolactin. Thus, mechanisms may exist for prolactin to promote investment in parental care without concurrent inhibition of reproductive function or HPG axis activity.
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Affiliation(s)
- Victoria S Farrar
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, United States of America.
| | - Laura Flores
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, United States of America
| | - Rechelle C Viernes
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, United States of America
| | - Laura Ornelas Pereira
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, United States of America
| | - Susan Mushtari
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, United States of America
| | - Rebecca M Calisi
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616, United States of America
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Dixit AS, Byrsat S, Singh NS. Circadian rhythm in photoperiodic expressions of GnRH-I and GnIH regulating seasonal reproduction in the Eurasian tree sparrow, Passer montanus. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 211:111993. [PMID: 32818912 DOI: 10.1016/j.jphotobiol.2020.111993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/03/2020] [Accepted: 08/09/2020] [Indexed: 10/23/2022]
Abstract
The present study investigates the involvement of circadian rhythm in photoperiodic expressions of GnRH-I and GnIH in the hypothalamus controlling seasonal reproduction in the Eurasian tree sparrow (Passer montanus). Groups of photosensitive birds were exposed for four weeks to resonance light dark cycles comprising of a light phase of 6 h (L) combined with dark phase of different durations (D) such that the period of LD cycles varied by 12 h increments viz. 12- (6 L/6D), 24- (6 L/18D), 36- (6 L/30D), 48- (6 L/42D), 60- (6 L/54D) and 72- (6 L/66D)h. In addition, a control group (C) was maintained under long day length (14 L/10D). Observations, recorded at the beginning and end of experiment, revealed significant testicular growth with corresponding increase in the hypothalamic expression of GnRH-I peptide but low levels of GnIH mRNA and peptide in the birds exposed to resonance cycles of 12, 36 and 60 h which were read as long days. On the other hand, birds experiencing resonance cycles of 24, 48 and 72 h read them as short days wherein they maintained their quiescent gonads and low levels of GnRH-I peptide but exhibited significant increase in GnIH mRNA and peptide expressions. Thus, sparrows responded to resonance light dark cycles differently despite the fact that each of them contained only 6 h of light. These findings suggest that an endogenous circadian rhythm is involved in photoperiodic expressions of above molecules and indicate a shift in their expressions depending upon whether the light falls in the photoinducible or non-photoinducible phase of an endogenous circadian rhythm.
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Affiliation(s)
- Anand S Dixit
- Department of Zoology, North Eastern Hill University, Shillong-22, Meghalaya, India.
| | - Sanborlang Byrsat
- Department of Zoology, North Eastern Hill University, Shillong-22, Meghalaya, India
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Son YL, Ubuka T, Tsutsui K. Molecular Mechanisms of Gonadotropin-Inhibitory Hormone (GnIH) Actions in Target Cells and Regulation of GnIH Expression. Front Endocrinol (Lausanne) 2019; 10:110. [PMID: 30858828 PMCID: PMC6397841 DOI: 10.3389/fendo.2019.00110] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/06/2019] [Indexed: 11/13/2022] Open
Abstract
Since gonadotropin-inhibitory hormone (GnIH) was discovered in 2000 as the first hypothalamic neuropeptide that actively inhibits gonadotropin release, researches conducted for the last 18 years have demonstrated that GnIH acts as a pronounced negative regulator of reproduction. Inhibitory effect of GnIH on reproduction is mainly accomplished at hypothalamic-pituitary levels; gonadotropin-releasing hormone (GnRH) neurons and gonadotropes are major targets of GnIH action based on the morphological interaction with GnIH neuronal fibers and the distribution of GnIH receptor. Here, we review molecular studies mainly focusing on the signal transduction pathway of GnIH in target cells, GnRH neurons, and gonadotropes. The use of well-defined cellular model systems allows the mechanistic study of signaling pathway occurring in target cells by demonstrating the direct cause-and-effect relationship. The insights gained through studying molecular mechanism of GnIH action contribute to deeper understanding of the mechanism of how GnIH communicates with other neuronal signaling systems to control our reproductive function. Reproductive axis closely interacts with other endocrine systems, thus GnIH expression levels would be changed by adrenal and thyroid status. We also briefly review molecular studies investigating the regulatory mechanisms of GnIH expression to understand the role of GnIH as a mediator between adrenal, thyroid and gonadal axes.
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Affiliation(s)
- You Lee Son
- Laboratory of Photobiology, Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
- *Correspondence: You Lee Son
| | - Takayoshi Ubuka
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Tokyo, Japan
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Dixit AS, Byrsat S. Photoperiodic control of GnRH-I expression in seasonal reproduction of the Eurasian tree sparrow. Photochem Photobiol Sci 2018; 17:934-945. [DOI: 10.1039/c8pp00153g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Day length has been shown to be a major source of temporal information regulating seasonal reproduction in the Eurasian tree sparrow (Passer montanus).
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Rastogi A, Malik S, Rani S, Kumar V. Changes in brain peptides associated with reproduction and energy homeostasis in photosensitive and photorefractory migratory redheaded buntings. Gen Comp Endocrinol 2016; 230-231:67-75. [PMID: 27038875 DOI: 10.1016/j.ygcen.2016.03.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 03/09/2016] [Accepted: 03/26/2016] [Indexed: 11/16/2022]
Abstract
Present study examined the expression of brain peptides associated with the reproduction and energy homeostasis (GnRH/GnIH, NPY/VIP), and assessed their possible functional association in the photosensitive (non-breeding, pre-breeding), photostimulated (breeding) and photorefractory (post-breeding) migratory redheaded buntings (Emberiza bruniceps), using double-labeled immunohistochemistry. Particularly, we measured immunoreactive (-ir) cell numbers, per cent cell area and cell optical density (OD) in the preoptic area (GnRH-I), midbrain (GnRH-II), paraventricular nucleus (GnIH), dorsomedial hypothalamus, DMH and infundibular complex, INc (NPY and VIP), and lateral septal organ (VIP) of buntings kept under natural photoperiods at the wintering latitude (26°55'N). There was a significant seasonal difference in GnRH-I, not GnRH-II, with reduced -ir cells in the photosensitive and photorefractory buntings, and notably with increased cell OD between the refractory and non-breeding states with no increase in testis size. Also, increased cell OD of GnIH neurons in non-breeding state indicated its role in the maintenance of small testes during the post-refractory period. Overall, seasonal changes in GnRH-I and GnIH were found consistent with their suggested roles in reproductive regulation of absolute photorefractory birds. Further, there was a significant seasonal change in cell OD of NPY neurons in DMH, not the INc. In contrast, VIP immunoreactivity was seasonally altered, with a significantly higher VIP-ir cells in breeding than the pre-breeding state. Finally, close proximity between perikarya with fibres suggested functional interactions between the GnRH and GnIH, and NPY and VIP. Thus, seasonal plasticity of brain peptides is perhaps the part of neural regulation of seasonal reproduction and associated energy homeostasis in migratory songbirds.
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Affiliation(s)
- Ashutosh Rastogi
- Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Shalie Malik
- Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Sangeeta Rani
- Department of Zoology, University of Lucknow, Lucknow 226 007, India
| | - Vinod Kumar
- Department of Zoology, University of Delhi, Delhi 110 007, India.
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Small TW, Brenowitz EA, Wojtenek W, Moore IT. Testosterone Mediates Seasonal Growth of the Song Control Nuclei in a Tropical Bird. BRAIN, BEHAVIOR AND EVOLUTION 2015; 86:110-21. [PMID: 26346733 DOI: 10.1159/000437412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/24/2015] [Indexed: 11/19/2022]
Abstract
In mid- to high-latitude songbirds, seasonal reproduction is stimulated by increasing day length accompanied by elevated plasma sex steroid levels, increased singing, and growth of the song control nuclei (SCN). Plasticity of the SCN and song behavior are primarily mediated by testosterone (T) and its metabolites in most species studied thus far. However, the majority of bird species are tropical and have less pronounced seasonal reproductive cycles. We have previously documented that equatorial rufous-collared sparrows (Zonotrichia capensis) exhibit seasonal neuroplasticity in the SCN. Manipulating T in these birds, however, did not alter singing behavior. In the current study, we investigated whether T mediates plasticity of the SCN in a similar manner to temperate songbirds. In the first experiment, we treated captive male birds with T or blank implants during the nonbreeding season. In a second experiment, we treated captive male birds with either blank implants, T-filled implants, T with flutamide (FLU; an androgen receptor antagonist) or T with FLU and 1,4,6-androstatriene-3,17-dione (ATD; an estrogen synthesis inhibitor) during the breeding season. In both experiments, the volumes of the brain areas high vocal center (HVC), Area X, and robust nucleus of the arcopallium (RA) were measured along with singing behavior. In summary, T stimulated growth of HVC and RA, and the combined effect of FLU and ATD reversed this effect in HVC. Area X was not affected by T treatment in either experiment. Neither T-treated birds nor controls sang in captivity during either experiment. Together, these data indicate that T mediates seasonal changes in the HVC and RA of both tropical and higher- latitude bird species even if the environmental signals differ. However, unlike most higher-latitude songbirds, we found no evidence that motivation to sing or growth of Area X are stimulated by T under captive conditions.
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Affiliation(s)
- Thomas W Small
- Department of Biological Sciences, Virginia Tech, Blacksburg, Va., USA
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Dixit AS, Singh NS. Seasonal Variation in Sensitivity of the Photoperiodic Response System in the Subtropical Tree Sparrow (Passer montanus). ACTA ACUST UNITED AC 2012; 317:488-98. [DOI: 10.1002/jez.1741] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 04/14/2012] [Accepted: 06/05/2012] [Indexed: 11/09/2022]
Affiliation(s)
- Anand S. Dixit
- Department of Zoology; North-Eastern Hill University; Shillong; Meghalaya; India
| | - Namram S. Singh
- Department of Zoology; North-Eastern Hill University; Shillong; Meghalaya; India
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Dawson A, Sharp PJ. Seasonal changes in concentrations of plasma LH and prolactin associated with the advance in the development of photorefractoriness and molt by high temperature in the starling. Gen Comp Endocrinol 2010; 167:122-7. [PMID: 20152838 DOI: 10.1016/j.ygcen.2010.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 02/03/2010] [Accepted: 02/05/2010] [Indexed: 11/20/2022]
Abstract
In a study on starlings (Sturnus vulgaris) kept on a simulated annual cycle in photoperiod, temperature had no effect on the timing or rate of testicular maturation but high temperature resulted in an advance in the timing of testicular regression and molt (Dawson, 2005). This study asks whether the earlier gonadal regression in response to higher temperature represents a central neuroendocrine response to temperature, and secondly, whether prolactin plays a role in the earlier regression. Castrated starlings were kept on a simulated annual cycle of photoperiod at either 8 or 18 degrees C. Circulating LH and prolactin concentrations were measured and the progress of the post-nuptial molt was recorded as an external indicator of the development of photorefractoriness. Additionally plasma prolactin was measured in samples taken from intact male and female starlings in the 2005 study. In castrated birds, LH concentrations decreased three weeks earlier at 18 degrees C. These birds also showed the same three week advance in molt as males and females in the earlier study. This demonstrates that the advance in regression caused by higher temperatures probably results from a central neuroendocrine mechanism, i.e., an advance in photorefractoriness, rather than an effect at the level of the gonads. Temperature had a highly significant effect on the changes in prolactin - peak prolactin occurred three weeks earlier at 18 degrees C. However, there was no clear consistent significant difference in prolactin between the two temperatures in advance of the onset of photorefractoriness, so the advance in photorefractoriness may not be mediated by prolactin. The higher temperature resulted in a significantly earlier decrease in prolactin and this may be causally related to the advance in molt.
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Affiliation(s)
- Alistair Dawson
- Centre for Ecology and Hydrology, Edinburgh, Bush Estate, Penicuik, Midlothian EH26 OQB, UK.
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Small TW, Moore IT. Seasonal neuroplasticity of the song control system in tropical, flexibly, and opportunistically breeding birds. Gen Comp Endocrinol 2009; 163:135-41. [PMID: 19344665 DOI: 10.1016/j.ygcen.2009.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 12/24/2008] [Accepted: 01/13/2009] [Indexed: 11/22/2022]
Abstract
The avian song control system is one of the primary models used to study neuroplasticity and neurogenesis in the adult vertebrate brain. A great deal of progress has been made in understanding the mechanisms controlling seasonal neuroplasticity of the song control system. However, relatively little work has been done to identify how prevalent this phenomenon is and if a diversity of environmental cues can regulate it. Photoperiod is the primary environmental cue used by mid- to high-latitude seasonally breeding birds to time growth of the song control system but many birds display flexible or opportunistic breeding patterns that are less reliant on photoperiodic cues. In addition, approximately 75% of birds are tropical and in only one such species has neuroplasticity of the song control system been studied. Our goal is to outline some of what is known and expand on the ways that studying tropical, flexibly, and opportunistically breeding birds can advance our understanding of plasticity in the song bird brain.
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Affiliation(s)
- Thomas W Small
- Department of Biological Sciences, Virginia Polytechnique Institute and State University, 2119 Derring Hall, Virginia Tech, Blacksburg, VA 24061, USA
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Deviche P. Reproductive physiology: songbird study removes long-standing neuroendocrinology research roadblock. Endocrinology 2009; 150:1561-2. [PMID: 19307417 DOI: 10.1210/en.2008-1818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Pierre Deviche
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501, USA.
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Deviche P, Sabo J, Sharp PJ. Glutamatergic stimulation of luteinising hormone secretion in relatively refractory male songbirds. J Neuroendocrinol 2008; 20:1191-202. [PMID: 18673412 DOI: 10.1111/j.1365-2826.2008.01771.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Seasonal breeding in two Sonoran desert passerines, the Cassin's (Aimophila cassinii) and Rufous-crowned (Aimophila ruficeps) Sparrows is thought to be terminated by the development of a decrease in responsiveness to photostimulation, a condition known as relative photorefractoriness. It was predicted that the development of relative refractoriness is a consequence of a decrease in gonadotrophin-releasing hormone (GnRH) synthesis and associated stores of releasable GnRH. This hypothesis was tested by determining the luteinising hormone (LH) responses to the excitatory amino acid glutamate agonist N-methyl-D,L-aspartate (NMA) in males of the two species subjected to photomanipulations aimed at generating five groups: Fully photosensitive with undeveloped testes on short days (8L : 16D); fully photosensitive with developed testes on 13L : 11D; relatively photorefractory with regressed testes on 13L : 11D, and groups with developed testes held on 15L : 9D or 16L : 8D. LH release was stimulated in the Cassin's Sparrow by NMA most in the 8L group; to a lesser, but similar extent in the two 13L groups; and not at all in the 15L and 16L groups. LH release was not stimulated by NMA in any of the photoperiodic regimes in the Rufous-crowned Sparrow. In both species, NMA induced Fos-like immunoreactivity in the anterior and basal hypothalamus, but not in GnRH cell bodies. It is concluded that the development of relative photorefractoriness in Cassin's Sparrows is a consequence of reduced GnRH synthesis, reflected in a reduction in releasable GnRH. The lack of LH response of the Rufous-crowned Sparrows to NMA administration may be a consequence of high responsiveness to handling stress.
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Affiliation(s)
- P Deviche
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
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