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Ainani H, El Bousmaki N, Poirel VJ, Achaâban MR, Ouassat M, Piro M, Klosen P, Simonneaux V, El Allali K. The dromedary camel displays annual variation in hypothalamic kisspeptin and Arg-Phe-amide-related peptide-3 according to sex, season, and breeding activity. J Comp Neurol 2019; 528:32-47. [PMID: 31251823 DOI: 10.1002/cne.24736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 01/25/2023]
Abstract
The dromedary camel (Camelus dromedarius) is a desert mammal whose cycles in reproductive activity ensure that the offspring's birth and weaning coincide with periods of abundant food resources and favorable climate conditions. In this study, we assessed whether kisspeptin (Kp) and arginine-phenylalanine (RF)-amide related peptide-3 (RFRP-3), two hypothalamic peptides known to regulate the mammalian hypothalamo-pituitary gonadal axis, may be involved in the seasonal control of camel's reproduction. Using specific antibodies and riboprobes, we found that Kp neurons are present in the preoptic area (POA), suprachiasmatic (SCN), and arcuate (ARC) nuclei, and that RFRP-3 neurons are present in the paraventricular (PVN), dorsomedial (DMH), and ventromedial (VMH) hypothalamic nuclei. Kp fibers are found in various hypothalamic areas, notably the POA, SCN, PVN, DMH, VMH, supraoptic nucleus, and the ventral and dorsal premammillary nucleus. RFRP-3 fibers are found in the POA, SCN, PVN, DMH, VMH, and ARC. POA and ARC Kp neurons and DMH RFRP-3 neurons display sexual dimorphism with more neurons in female than in male. Both neuronal populations display opposed seasonal variations with more Kp neurons and less RFRP-3 neurons during the breeding (December-January) than the nonbreeding (July-August) season. This study is the first describing Kp and RFRP-3 in the camel's brain with, during the winter period lower RFRP-3 expression and higher Kp expression possibly responsible for the HPG axis activation. Altogether, our data indicate the involvement of both Kp and RFRP-3 in the seasonal control of the dromedary camel's breeding activity.
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Affiliation(s)
- Hassan Ainani
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco.,Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Najlae El Bousmaki
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Vincent-Joseph Poirel
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Mohamed Rachid Achaâban
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Mohammed Ouassat
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Mohammed Piro
- Medicine and Surgical Unit of Domestic animals, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
| | - Paul Klosen
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Valérie Simonneaux
- Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, Strasbourg, France
| | - Khalid El Allali
- Comparative Anatomy Unit, Hassan II Agronomy and Veterinary Institute, Rabat Instituts, Rabat, Morocco
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Karatsoreos IN. Circadian Regulation of the Brain and Behavior: A Neuroendocrine Perspective. Curr Top Behav Neurosci 2019; 43:323-351. [PMID: 31586337 DOI: 10.1007/7854_2019_115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neuroendocrine systems are key regulators of brain and body functions, providing an important nexus between internal states and the external world, which then modulates appropriate behavioral outputs. Circadian (daily) rhythms are endogenously generated rhythms of approximately 24 h that help to synchronize internal physiological processes and behavioral states to the external environmental light-dark cycle. Given the importance of timing (hours, days, annual) in many different neuroendocrine axes, understanding how the circadian timing system regulates neuroendocrine function is particularly critical. Similarly, neuroendocrine signals can significantly affect circadian timing, and understanding these mechanisms can provide insights into general concepts of neuroendocrine regulation of brain circuits and behavior. This chapter will review the circadian timing system and its control of two key neuroendocrine systems: the hypothalamic-pituitary-gonadal (HPG) axis and the hypothalamic-pituitary-adrenal (HPA) axis. It will also discuss how outputs from these axes feedback to affect the circadian clock. Given that disruption of circadian timing is a central component of many mental and physical health conditions and that neuroendocrine function is similarly implicated in many of the same conditions, understanding these links will help illuminate potentially shared causality and perhaps lead to a better understanding of how to manipulate these systems when they begin to malfunction.
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Affiliation(s)
- Ilia N Karatsoreos
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA, USA.
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Wood S, Loudon A. The pars tuberalis: The site of the circannual clock in mammals? Gen Comp Endocrinol 2018; 258:222-235. [PMID: 28669798 DOI: 10.1016/j.ygcen.2017.06.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Abstract
Accurate timing and physiological adaptation to anticipate seasonal changes are an essential requirement for an organism's survival. In contrast to all other environmental cues, photoperiod offers a highly predictive signal that can be reliably used to activate a seasonal adaptive programme at the correct time of year. Coupled to photoperiod sensing, it is apparent that many organisms have evolved innate long-term timekeeping systems, allowing reliable anticipation of forthcoming environmental changes. The fundamental biological processes giving rise to innate long-term timing, with which the photoperiod-sensing pathway engages, are not known for any organism. There is growing evidence that the pars tuberalis (PT) of the pituitary, which acts as a primary transducer of photoperiodic input, may be the site of the innate long-term timer or "circannual clock". Current research has led to the proposition that the PT-specific thyrotroph may act as a seasonal calendar cell, driving both hypothalamic and pituitary endocrine circuits. Based on this research we propose that the mechanistic basis for the circannual rhythm appears to be deeply conserved, driven by a binary switching cell based accumulator, analogous to that proposed for development. We review the apparent conservation of function and pathways to suggest that these broad principles may apply across the vertebrate lineage and even share characteristics with processes driving seasonal adaptation in plants.
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Affiliation(s)
- Shona Wood
- Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, A.V. Hill Building, Oxford Road, Manchester M13 9PT, UK.
| | - Andrew Loudon
- Faculty of Biology, Medicine and Health, School of Medical Sciences, University of Manchester, A.V. Hill Building, Oxford Road, Manchester M13 9PT, UK
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Abstract
Female ovulation depends on a surge in circulating luteinizing hormone (LH) which occurs at the end of the resting period and requests high circulating estradiol. This fine tuning involves both an estradiol feedback as an indicator of oocyte maturation, and the master circadian clock of the suprachiasmatic nuclei as an indicator of the time of the day. This review describes the mechanisms through which daily time cues are conveyed to reproductive hypothalamic neurons to time the pre-ovulatory surge. In female rodents, neurotransmitters released by the suprachiasmatic nuclei activate the stimulatory kisspeptin neurons and reduce the inhibitory RFRP neurons precisely at the end of the afternoon of proestrus to allow a full surge in LH secretion. From these findings, the impact of circadian disruptions (during shift or night work) on female reproductive performance and fertility should now being investigated in both animal models and humans.
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Affiliation(s)
- Valérie Simonneaux
- Institut des Neurosciences Cellulaires et Intégratives, UPR CNRS 3212, 5 rue Blaise Pascal, 67084 Strasbourg, France.
| | - Thibault Bahougne
- Institut des Neurosciences Cellulaires et Intégratives, UPR CNRS 3212, 5 rue Blaise Pascal, 67084 Strasbourg, France; Service d'Endocrinologie et Diabète, Hôpital Civil, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
| | - Eleni Angelopoulou
- Institut des Neurosciences Cellulaires et Intégratives, UPR CNRS 3212, 5 rue Blaise Pascal, 67084 Strasbourg, France; Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, Netherlands.
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XU L, XUE H, LI S, XU J, CHEN L. Seasonal differential expression of KiSS-1/GPR54
in the striped hamsters (Cricetulus barabensis
) among different tissues. Integr Zool 2017; 12:260-268. [DOI: 10.1111/1749-4877.12223] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laixiang XU
- College of Life Sciences; Qufu Normal University; Qufu Shandong China
| | - Huiliang XUE
- College of Life Sciences; Qufu Normal University; Qufu Shandong China
| | - Shenning LI
- College of Life Sciences; Qufu Normal University; Qufu Shandong China
| | - Jinhui XU
- College of Life Sciences; Qufu Normal University; Qufu Shandong China
| | - Lei CHEN
- College of Life Sciences; Qufu Normal University; Qufu Shandong China
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Aytürk N, Firat T, Kükner A, Özoğul C, Töre F, Kandirali İE, Yilmaz B. The effect of kisspeptin on spermatogenesis and apoptosis in rats. Turk J Med Sci 2017; 47:334-342. [PMID: 28263511 DOI: 10.3906/sag-1505-69] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 04/21/2016] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND/AIM To study the effect of kisspeptin, a gonadotropin release stimulator, on the testicular tissue of the rat. MATERIALS AND METHODS Four groups were formed as follows: control, Kiss-10 501397645907nmol administration for 1 day, Kiss-10 administration for 13 days, and one last group kept for 7 days following Kiss-10 applied for 13 days. Testicular tissues were stained with hematoxylin-eosin, periodic acid Schiff, Masson trichrome staining, terminal deoxynucleotidyl transferased UTP nick-end labeling, and Ki-67 immune staining. Serum testosterone levels were determined. RESULTS Serum testosterone level increased following acute application, while it was reduced by chronic treatment. Spermatogenic cells as stained by Ki-67 and TUNEL increased in the treated groups compared to the controls. Following a 7-day rest after treatment, a decrease in testosterone levels and Ki-67-stained cell numbers and an increase in TUNEL-stained cells were observed. Leydig cells showed increased vacuolization in the Kiss-1 group. Leydig cell vacuolization continued in the Kiss (13) group and was reduced in the Kiss (13 + 7) group. CONCLUSION Kiss-10 increased spermatogenic cell proliferation, while testosterone level and proliferation decreased and apoptosis increased during the waiting period.
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Affiliation(s)
- Nilüfer Aytürk
- Department of Histology and Embryology, Faculty of Medicine, Medipol University, İstanbul, Turkey
| | - Tülin Firat
- Department of Histology and Embryology, Faculty of Medicine, Abant İzzet Baysal University, Bolu, Turkey
| | - Aysel Kükner
- Department of Histology and Embryology, Faculty of Medicine, Abant İzzet Baysal University, Bolu, Turkey
| | - Candan Özoğul
- Department of Histology and Embryology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Fatma Töre
- Department of Physiology, Faculty of Medicine, SANKO University, Gaziantep, Turkey
| | - İsmail Engin Kandirali
- Department of Urology Clinics, Bağcılar Education and Research Hospital, İstanbul, Turkey
| | - Bayram Yilmaz
- Department of Physiology, Faculty of Medicine, İstanbul Yeditepe University, İstanbul, Turkey
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Alvarado MV, Carrillo M, Felip A. Melatonin-induced changes in kiss/gnrh gene expression patterns in the brain of male sea bass during spermatogenesis. Comp Biochem Physiol A Mol Integr Physiol 2015; 185:69-79. [DOI: 10.1016/j.cbpa.2015.03.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/11/2015] [Accepted: 03/16/2015] [Indexed: 01/04/2023]
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8
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Migaud M, Butrille L, Batailler M. Seasonal regulation of structural plasticity and neurogenesis in the adult mammalian brain: focus on the sheep hypothalamus. Front Neuroendocrinol 2015; 37:146-57. [PMID: 25462590 DOI: 10.1016/j.yfrne.2014.11.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 01/19/2023]
Abstract
To cope with variations in the environment, most mammalian species exhibit seasonal cycles in physiology and behaviour. Seasonal plasticity during the lifetime contributes to seasonal physiology. Over the years, our ideas regarding adult brain plasticity and, more specifically, hypothalamic plasticity have greatly evolved. Along with the two main neurogenic regions, namely the hippocampal subgranular and lateral ventricle subventricular zones, the hypothalamus, which is the central homeostatic regulator of numerous physiological functions that comprise sexual behaviours, feeding and metabolism, also hosts neurogenic niches. Both endogenous and exogenous factors, including the photoperiod, modulate the hypothalamic neurogenic capacities. The present review describes the effects of season on adult morphological plasticity and neurogenesis in seasonal species, for which the photoperiod is a master environmental cue for the successful programming of seasonal functions. In addition, the potential functional significance of adult neurogenesis in the mediation of the seasonal control of reproduction and feeding is discussed.
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Affiliation(s)
- Martine Migaud
- INRA, UMR 85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université de Tours, F-37041 Tours, France; Haras Nationaux, F-37380 Nouzilly, France.
| | - Lucile Butrille
- INRA, UMR 85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université de Tours, F-37041 Tours, France; Haras Nationaux, F-37380 Nouzilly, France
| | - Martine Batailler
- INRA, UMR 85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France; CNRS, UMR7247, F-37380 Nouzilly, France; Université de Tours, F-37041 Tours, France; Haras Nationaux, F-37380 Nouzilly, France
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9
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Simonneaux V, Bahougne T. A Multi-Oscillatory Circadian System Times Female Reproduction. Front Endocrinol (Lausanne) 2015; 6:157. [PMID: 26539161 PMCID: PMC4611855 DOI: 10.3389/fendo.2015.00157] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/21/2015] [Indexed: 01/14/2023] Open
Abstract
Rhythms in female reproduction are critical to insure that timing of ovulation coincides with oocyte maturation and optimal sexual arousal. This fine tuning of female reproduction involves both the estradiol feedback as an indicator of oocyte maturation, and the master circadian clock of the suprachiasmatic nuclei (SCN) as an indicator of the time of the day. Herein, we are providing an overview of the state of knowledge regarding the differential inhibitory and stimulatory effects of estradiol at different stages of the reproductive axis, and the mechanisms through which the two main neurotransmitters of the SCN, arginine vasopressin, and vasoactive intestinal peptide, convey daily time cues to the reproductive axis. In addition, we will report the most recent findings on the putative functions of peripheral clocks located throughout the reproductive axis [kisspeptin (Kp) neurons, gonadotropin-releasing hormone neurons, gonadotropic cells, the ovary, and the uterus]. This review will point to the critical position of the Kp neurons of the anteroventral periventricular nucleus, which integrate both the stimulatory estradiol signal, and the daily arginine vasopressinergic signal, while displaying a circadian clock. Finally, given the critical role of the light/dark cycle in the synchronization of female reproduction, we will discuss the impact of circadian disruptions observed during shift-work conditions on female reproductive performance and fertility in both animal model and humans.
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Affiliation(s)
- Valérie Simonneaux
- Institut des Neurosciences Cellulaires et Intégratives, CNRS (UPR 3212), Strasbourg, France
- *Correspondence: Valérie Simonneaux, Institut des Neurosciences Cellulaires et Intégratives, CNRS (UPR 3212), 5 rue Blaise Pascal, Strasbourg 67084, France,
| | - Thibault Bahougne
- Institut des Neurosciences Cellulaires et Intégratives, CNRS (UPR 3212), Strasbourg, France
- Service d’Endocrinologie et Diabète, Hôpital Civil, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
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10
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Wood S, Loudon A. Clocks for all seasons: unwinding the roles and mechanisms of circadian and interval timers in the hypothalamus and pituitary. J Endocrinol 2014; 222:R39-59. [PMID: 24891434 PMCID: PMC4104039 DOI: 10.1530/joe-14-0141] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adaptation to the environment is essential for survival, in all wild animal species seasonal variation in temperature and food availability needs to be anticipated. This has led to the evolution of deep-rooted physiological cycles, driven by internal clocks, which can track seasonal time with remarkable precision. Evidence has now accumulated that a seasonal change in thyroid hormone (TH) availability within the brain is a crucial element. This is mediated by local control of TH-metabolising enzymes within specialised ependymal cells lining the third ventricle of the hypothalamus. Within these cells, deiodinase type 2 enzyme is activated in response to summer day lengths, converting metabolically inactive thyroxine (T4) to tri-iodothyronine (T3). The availability of TH in the hypothalamus appears to be an important factor in driving the physiological changes that occur with season. Remarkably, in both birds and mammals, the pars tuberalis (PT) of the pituitary gland plays an essential role. A specialised endocrine thyrotroph cell (TSH-expressing) is regulated by the changing day-length signal, leading to activation of TSH by long days. This acts on adjacent TSH-receptors expressed in the hypothalamic ependymal cells, causing local regulation of deiodinase enzymes and conversion of TH to the metabolically active T3. In mammals, the PT is regulated by the nocturnal melatonin signal. Summer-like melatonin signals activate a PT-expressed clock-regulated transcription regulator (EYA3), which in turn drives the expression of the TSHβ sub-unit, leading to a sustained increase in TSH expression. In this manner, a local pituitary timer, driven by melatonin, initiates a cascade of molecular events, led by EYA3, which translates to seasonal changes of neuroendocrine activity in the hypothalamus. There are remarkable parallels between this PT circuit and the photoperiodic timing system used in plants, and while plants use different molecular signals (constans vs EYA3) it appears that widely divergent organisms probably obey a common set of design principles.
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Affiliation(s)
- Shona Wood
- Faculty of Life SciencesUniversity of Manchester, Manchester M13 9PT, UK
| | - Andrew Loudon
- Faculty of Life SciencesUniversity of Manchester, Manchester M13 9PT, UK
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11
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Decourt C, Caraty A, Briant C, Guillaume D, Lomet D, Chesneau D, Lardic L, Duchamp G, Reigner F, Monget P, Dufourny L, Beltramo M, Dardente H. Acute Injection and Chronic Perfusion of Kisspeptin Elicit Gonadotropins Release but Fail to Trigger Ovulation in the Mare1. Biol Reprod 2014; 90:36. [DOI: 10.1095/biolreprod.113.114157] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Reiter RJ, Tan DX, Tamura H, Cruz MHC, Fuentes-Broto L. Clinical relevance of melatonin in ovarian and placental physiology: a review. Gynecol Endocrinol 2014; 30:83-9. [PMID: 24319996 DOI: 10.3109/09513590.2013.849238] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Within the last decade, the synthesis of melatonin in and its functions at the level of the peripheral reproductive organs has come into better focus. Melatonin is produced at several reproductive organ sites, e.g., the oocyte, ovarian follicular cells and the placental cytotrophoblasts. Moreover, these cells also contain membrane receptors for this indoleamine. In addition, via the free radical scavenging activity of melatonin and its metabolites, oxidative stress is reduced in all reproductive organ cells ensuring their optimal function. Enhancement of oocyte maturation and preservation of oocyte quality may be major functions of melatonin. Oocyte damage reduces successful fertilization and the development of a healthy fetus. The findings that melatonin protects the oocyte from toxic oxygen species have implications for improving the outcome of in vitro fertilization-embryo transfer procedures, as already shown in two published reports. Some actions of melatonin in the placenta may be context specific. Thus, melatonin is believed to function in the maintenance of optimal placental homeostasis by deferring apoptosis of villous cytotrophoblasts, while protecting syncytiotrophoblasts from oxidative damage. Melatonin reduces oxidative damage in the placenta and may improve hemodynamics and nutrient transfer at the placental-uterine interface. The use of melatonin to treat preeclampsia should also be considered.
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Affiliation(s)
- Russel J Reiter
- Department of Cellular and Structural Biology, UT Health Science Center , San Antonio, TX , USA
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13
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Beltramo M, Dardente H, Cayla X, Caraty A. Cellular mechanisms and integrative timing of neuroendocrine control of GnRH secretion by kisspeptin. Mol Cell Endocrinol 2014; 382:387-399. [PMID: 24145132 DOI: 10.1016/j.mce.2013.10.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 10/08/2013] [Accepted: 10/11/2013] [Indexed: 01/11/2023]
Abstract
The hypothalamus integrates endogenous and exogenous inputs to control the pituitary-gonadal axis. The ultimate hypothalamic influence on reproductive activity is mediated through timely secretion of GnRH in the portal blood, which modulates the release of gonadotropins from the pituitary. In this context neurons expressing the RF-amide neuropeptide kisspeptin present required features to fulfill the role of the long sought-after hypothalamic integrative centre governing the stimulation of GnRH neurons. Here we focus on the intracellular signaling pathways triggered by kisspeptin through its cognate receptor KISS1R and on the potential role of proteins interacting with this receptor. We then review evidence implicating both kisspeptin and RFRP3--another RF-amide neuropeptide--in the temporal orchestration of both the pre-ovulatory LH surge in female rodents and the organization of seasonal breeding in photoperiodic species.
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Affiliation(s)
- Massimiliano Beltramo
- UMR Physiologie de la Reproduction et des Comportements (INRA, UMR85, CNRS, UMR7247, Université François Rabelais Tours, IFCE), F-37380 Nouzilly, France.
| | - Hugues Dardente
- UMR Physiologie de la Reproduction et des Comportements (INRA, UMR85, CNRS, UMR7247, Université François Rabelais Tours, IFCE), F-37380 Nouzilly, France
| | - Xavier Cayla
- UMR Physiologie de la Reproduction et des Comportements (INRA, UMR85, CNRS, UMR7247, Université François Rabelais Tours, IFCE), F-37380 Nouzilly, France
| | - Alain Caraty
- UMR Physiologie de la Reproduction et des Comportements (INRA, UMR85, CNRS, UMR7247, Université François Rabelais Tours, IFCE), F-37380 Nouzilly, France
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14
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Dardente H, Hazlerigg DG, Ebling FJP. Thyroid hormone and seasonal rhythmicity. Front Endocrinol (Lausanne) 2014; 5:19. [PMID: 24616714 PMCID: PMC3935485 DOI: 10.3389/fendo.2014.00019] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/10/2014] [Indexed: 12/15/2022] Open
Abstract
Living organisms show seasonality in a wide array of functions such as reproduction, fattening, hibernation, and migration. At temperate latitudes, changes in photoperiod maintain the alignment of annual rhythms with predictable changes in the environment. The appropriate physiological response to changing photoperiod in mammals requires retinal detection of light and pineal secretion of melatonin, but extraretinal detection of light occurs in birds. A common mechanism across all vertebrates is that these photoperiod-regulated systems alter hypothalamic thyroid hormone (TH) conversion. Here, we review the evidence that a circadian clock within the pars tuberalis of the adenohypophysis links photoperiod decoding to local changes of TH signaling within the medio-basal hypothalamus (MBH) through a conserved thyrotropin/deiodinase axis. We also focus on recent findings which indicate that, beyond the photoperiodic control of its conversion, TH might also be involved in longer-term timing processes of seasonal programs. Finally, we examine the potential implication of kisspeptin and RFRP3, two RF-amide peptides expressed within the MBH, in seasonal rhythmicity.
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Affiliation(s)
- Hugues Dardente
- Physiologie de la Reproduction et des Comportements, INRA, UMR085, Nouzilly, France
- CNRS, UMR7247, Nouzilly, France
- Université François Rabelais de Tours, Tours, France
- Institut français du cheval et de l’équitation, Nouzilly, France
- *Correspondence: Hugues Dardente, INRA, UMR85 Physiologie de la Reproduction et des Comportements, CNRS, UMR7247, Université François Rabelais de Tours, IFCE, F-37380 Nouzilly, France e-mail:
| | - David G. Hazlerigg
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
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15
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Tsutsui K, Ubuka T, Bentley GE, Kriegsfeld LJ. Review: regulatory mechanisms of gonadotropin-inhibitory hormone (GnIH) synthesis and release in photoperiodic animals. Front Neurosci 2013; 7:60. [PMID: 23596387 PMCID: PMC3627135 DOI: 10.3389/fnins.2013.00060] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 04/01/2013] [Indexed: 01/08/2023] Open
Abstract
Gonadotropin-inhibitory hormone (GnIH) is a novel hypothalamic neuropeptide that was discovered in quail as an inhibitory factor for gonadotropin release. GnIH inhibits gonadotropin synthesis and release in birds through actions on gonadotropin-releasing hormone (GnRH) neurons and gonadotropes, mediated via the GnIH receptor (GnIH-R), GPR147. Subsequently, GnIH was identified in mammals and other vertebrates. As in birds, mammalian GnIH inhibits gonadotropin secretion, indicating a conserved role for this neuropeptide in the control of the hypothalamic-pituitary-gonadal (HPG) axis across species. Identification of the regulatory mechanisms governing GnIH expression and release is important in understanding the physiological role of the GnIH system. A nocturnal hormone, melatonin, appears to act directly on GnIH neurons through its receptor to induce expression and release of GnIH in quail, a photoperiodic bird. Recently, a similar, but opposite, action of melatonin on the inhibition of expression of mammalian GnIH was shown in hamsters and sheep, photoperiodic mammals. These results in photoperiodic animals demonstrate that GnIH expression is photoperiodically modulated via a melatonin-dependent process. Recent findings indicate that GnIH may be a mediator of stress-induced reproductive disruption in birds and mammals, pointing to a broad role for this neuropeptide in assessing physiological state and modifying reproductive effort accordingly. This paper summarizes the advances made in our knowledge regarding the regulation of GnIH synthesis and release in photoperiodic birds and mammals. This paper also discusses the neuroendocrine integration of environmental signals, such as photoperiods and stress, and internal signals, such as GnIH, melatonin, and glucocorticoids, to control avian and mammalian reproduction.
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Affiliation(s)
- Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, and Center for Medical Life Science of Waseda University Tokyo, Japan
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