Kisspeptins and Reproduction: Physiological Roles and Regulatory Mechanisms

2012 ◽  
Vol 92 (3) ◽  
pp. 1235-1316 ◽  
Author(s):  
Leonor Pinilla ◽  
Enrique Aguilar ◽  
Carlos Dieguez ◽  
Robert P. Millar ◽  
Manuel Tena-Sempere
Keyword(s):  
Biological Effects ◽  
Reproductive Function ◽  
Future Research ◽  
Gonadotropin Secretion ◽  
Integral Control ◽  
Molecular Features ◽  
Hypothalamic Nuclei ◽  
Key Aspects ◽  
And Function ◽  
The Brain

Procreation is essential for survival of species. Not surprisingly, complex neuronal networks have evolved to mediate the diverse internal and external environmental inputs that regulate reproduction in vertebrates. Ultimately, these regulatory factors impinge, directly or indirectly, on a final common pathway, the neurons producing the gonadotropin-releasing hormone (GnRH), which stimulates pituitary gonadotropin secretion and thereby gonadal function. Compelling evidence, accumulated in the last few years, has revealed that kisspeptins, a family of neuropeptides encoded by the Kiss1 gene and produced mainly by neuronal clusters at discrete hypothalamic nuclei, are pivotal upstream regulators of GnRH neurons. As such, kisspeptins have emerged as important gatekeepers of key aspects of reproductive maturation and function, from sexual differentiation of the brain and puberty onset to adult regulation of gonadotropin secretion and the metabolic control of fertility. This review aims to provide a comprehensive account of the state-of-the-art in the field of kisspeptin physiology by covering in-depth the consensus knowledge on the major molecular features, biological effects, and mechanisms of action of kisspeptins in mammals and, to a lesser extent, in nonmammalian vertebrates. This review will also address unsolved and contentious issues to set the scene for future research challenges in the area. By doing so, we aim to endow the reader with a critical and updated view of the physiological roles and potential translational relevance of kisspeptins in the integral control of reproductive function.

scholarly journals Sex Differences and the Influence of Sex Hormones on Cognition through Adulthood and the Aging Process

2018 ◽  
Vol 8 (9) ◽  
pp. 163 ◽  
Author(s):  
Caroline Gurvich ◽  
Kate Hoy ◽  
Natalie Thomas ◽  
Jayashri Kulkarni
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Sex Differences ◽  
Cognitive Functioning ◽  
Sex Hormones ◽  
Reproductive Function ◽  
Health And Disease ◽  
And Function ◽  
The Brain

Hormones of the hypothalamic-pituitary-gonadal (HPG) axis that regulate reproductive function have multiple effects on the development, maintenance and function of the brain. Sex differences in cognitive functioning have been reported in both health and disease, which may be partly attributed to sex hormones. The aim of the current paper was to provide a theoretical review of how sex hormones influence cognitive functioning across the lifespan as well as provide an overview of the literature on sex differences and the role of sex hormones in cognitive decline, specifically in relation to Alzheimer’s disease (AD). A summary of current hormone and sex-based interventions for enhancing cognitive functioning and/or reducing the risk of Alzheimer’s disease is also provided.

scholarly journals Maintenance of Gonadotropin Secretion by Glucocorticoids under Stress Conditions through the Inhibition of Prostaglandin Synthesis in the Brain

Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1087-1093 ◽  
Author(s):  
Takashi Matsuwaki ◽  
Yuko Kayasuga ◽  
Keitaro Yamanouchi ◽  
Masugi Nishihara
Keyword(s):  
Restraint Stress ◽  
Acute Stress ◽  
Reproductive Function ◽  
Stress Conditions ◽  
Ovariectomized Rats ◽  
Gonadotropin Secretion ◽  
Inhibition Of Prostaglandin Synthesis ◽  
Corticosterone Treatment ◽  
Factor Α ◽  
The Brain

We have previously reported that glucocorticoids counteract the suppressive effects of tumor necrosis factor-α on both pulsatile and surge secretion of LH. This suggests that glucocorticoids have a protective effect on reproductive function under infectious stress. In the present study, we examined whether glucocorticoids maintain pulsatile LH secretion under various conditions of acute stress and the possible involvement of prostaglandins (PGs) in glucocorticoid actions. Three different types of stressors, namely infectious (lipopolysaccharide, 0.5 μg/kg), hypoglycemic (2-deoxy-d-glucose, 100 mg/kg), and restraint stress (1 h) were applied to ovariectomized rats. In ovariectomized rats, LH pulses were partially suppressed by restraint, but not by lipopolysaccharide or 2-deoxy-d-glucose. On the other hand, adrenalectomy (ADX) significantly enhanced the suppressive effects of all the stressors applied on LH pulses. Treatment with both corticosterone (25 mg/kg) and indomethacin (10 mg/kg) in ADX rats significantly attenuated the suppressive effects of these stressors on LH pulses. In addition, the immunoreactivity of cyclooxygenase-2, a PG-synthesizing enzyme, in the brain under stress conditions was much enhanced by ADX, and this was counteracted by corticosterone treatment. Similarly, an increase in body temperature under restraint stress was enhanced by ADX and suppressed by corticosterone. These results suggest that suppression of LH pulsatility by stress is mediated by PGs in the brain, and that increased release of endogenous glucocorticoids in response to stress counteracts this suppression by inhibiting PG synthesis, and thereby maintains reproductive function regardless of the nature of the stressor.

scholarly journals Novel Insight Into the Development and Function of Hypopharyngeal Glands in Honey Bees

2021 ◽  
Vol 11 ◽  
Author(s):  
Saboor Ahmad ◽  
Shahmshad Ahmed Khan ◽  
Khalid Ali Khan ◽  
Jianke Li
Keyword(s):  
Honey Bees ◽  
Future Research ◽  
Factors Affecting ◽  
Hypopharyngeal Glands ◽  
And Function ◽  
First Time ◽  
The Brain ◽  
Insight Into ◽  
Made In

Hypopharyngeal glands (HGs) are the most important organ of hymenopterans which play critical roles for the insect physiology. In honey bees, HGs are paired structures located bilaterally in the head, in front of the brain between compound eyes. Each gland is composed of thousands of secretory units connecting to secretory duct in worker bees. To better understand the recent progress made in understanding the structure and function of these glands, we here review the ontogeny of HGs, and the factors affecting the morphology, physiology, and molecular basis of the functionality of the glands. We also review the morphogenesis of HGs in the pupal and adult stages, and the secretory role of the glands across the ages for the first time. Furthermore, recent transcriptome, proteome, and phosphoproteome analyses have elucidated the potential mechanisms driving the HGs development and functionality. This adds a comprehensive novel knowledge of the development and physiology of HGs in honey bees over time, which may be helpful for future research investigations.

scholarly journals Insight Into the Ontogeny of GnRH Neurons From Patients Born Without a Nose

2020 ◽  
Vol 105 (5) ◽  
pp. 1538-1551
Author(s):  
Angela Delaney ◽  
Rita Volochayev ◽  
Brooke Meader ◽  
Janice Lee ◽  
Konstantinia Almpani ◽  
...  
Keyword(s):  
Reproductive Function ◽  
Normal Breast ◽  
Breast Development ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Male Patients ◽  
And Function ◽  
Human Embryology ◽  
The Brain ◽  
Insight Into

Abstract Context The reproductive axis is controlled by a network of gonadotropin-releasing hormone (GnRH) neurons born in the primitive nose that migrate to the hypothalamus alongside axons of the olfactory system. The observation that congenital anosmia (inability to smell) is often associated with GnRH deficiency in humans led to the prevailing view that GnRH neurons depend on olfactory structures to reach the brain, but this hypothesis has not been confirmed. Objective The objective of this work is to determine the potential for normal reproductive function in the setting of completely absent internal and external olfactory structures. Methods We conducted comprehensive phenotyping studies in 11 patients with congenital arhinia. These studies were augmented by review of medical records and study questionnaires in another 40 international patients. Results All male patients demonstrated clinical and/or biochemical signs of GnRH deficiency, and the 5 men studied in person had no luteinizing hormone (LH) pulses, suggesting absent GnRH activity. The 6 women studied in person also had apulsatile LH profiles, yet 3 had spontaneous breast development and 2 women (studied from afar) had normal breast development and menstrual cycles, suggesting a fully intact reproductive axis. Administration of pulsatile GnRH to 2 GnRH-deficient patients revealed normal pituitary responsiveness but gonadal failure in the male patient. Conclusions Patients with arhinia teach us that the GnRH neuron, a key gatekeeper of the reproductive axis, is associated with but may not depend on olfactory structures for normal migration and function, and more broadly, illustrate the power of extreme human phenotypes in answering fundamental questions about human embryology.

scholarly journals Hypothalamic pathways linking energy balance and reproduction

2008 ◽  
Vol 294 (5) ◽  
pp. E827-E832 ◽  
Author(s):  
Jennifer W. Hill ◽  
Joel K. Elmquist ◽  
Carol F. Elias
Keyword(s):  
Energy Balance ◽  
Metabolic Pathways ◽  
Molecular Mechanisms ◽  
Arcuate Nucleus ◽  
Metabolic Stress ◽  
Reproductive Function ◽  
Reproductive Axis ◽  
Hypothalamic Nuclei ◽  
Adiposity Signals ◽  
The Brain

During periods of metabolic stress, animals must channel energy toward survival and away from processes such as reproduction. The reproductive axis, therefore, has the capacity to respond to changing levels of metabolic cues. The cellular and molecular mechanisms that link energy balance and reproduction, as well as the brain sites mediating this function, are still not well understood. This review focuses on the best characterized of the adiposity signals: leptin and insulin. We examine their reproductive role acting on the classic metabolic pathways of the arcuate nucleus, NPY/AgRP and POMC/CART neurons, and the newly identified kisspeptin network. In addition, other hypothalamic nuclei that may play a role in linking metabolic state and reproductive function are discussed. The nature of the interplay between these elements of the metabolic and reproductive systems presents a fascinating puzzle, whose pieces are just beginning to fall into place.

scholarly journals Microbiome–microglia connections via the gut–brain axis

2018 ◽  
Vol 216 (1) ◽  
pp. 41-59 ◽  
Author(s):  
Reem Abdel-Haq ◽  
Johannes C.M. Schlachetzki ◽  
Christopher K. Glass ◽  
Sarkis K. Mazmanian
Keyword(s):  
Immune Cells ◽  
Gut Microbiome ◽  
Neurological Disorders ◽  
Microbial Community Composition ◽  
Future Research ◽  
Gi Tract ◽  
Synaptic Remodeling ◽  
And Function ◽  
The Brain ◽  
Microglial Development

Microglia, the resident immune cells in the brain, are essential for modulating neurogenesis, influencing synaptic remodeling, and regulating neuroinflammation by surveying the brain microenvironment. Microglial dysfunction has been implicated in the onset and progression of several neurodevelopmental and neurodegenerative diseases; however, the multitude of factors and signals influencing microglial activity have not been fully elucidated. Microglia not only respond to local signals within the brain but also receive input from the periphery, including the gastrointestinal (GI) tract. Recent preclinical findings suggest that the gut microbiome plays a pivotal role in regulating microglial maturation and function, and altered microbial community composition has been reported in neurological disorders with known microglial involvement in humans. Collectively, these findings suggest that bidirectional crosstalk between the gut and the brain may influence disease pathogenesis. Herein, we discuss recent studies showing a role for the gut microbiome in modulating microglial development and function in homeostatic and disease conditions and highlight possible future research to develop novel microbial treatments for disorders of the brain.

scholarly journals A Window into the Brain: Advances in Psychiatric fMRI

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaoyan Zhan ◽  
Rongjun Yu
Keyword(s):  
Mental Illness ◽  
Brain Network ◽  
Psychiatric Research ◽  
Future Research ◽  
Functional Communication ◽  
Spatial And Temporal Patterns ◽  
Neural Basis ◽  
Brain Structure And Function ◽  
And Function ◽  
The Brain

Functional magnetic resonance imaging (fMRI) plays a key role in modern psychiatric research. It provides a means to assay differences in brain systems that underlie psychiatric illness, treatment response, and properties of brain structure and function that convey risk factor for mental diseases. Here we review recent advances in fMRI methods in general use and progress made in understanding the neural basis of mental illness. Drawing on concepts and findings from psychiatric fMRI, we propose that mental illness may not be associated with abnormalities in specific local regions but rather corresponds to variation in the overall organization of functional communication throughout the brain network. Future research may need to integrate neuroimaging information drawn from different analysis methods and delineate spatial and temporal patterns of brain responses that are specific to certain types of psychiatric disorders.

Using neuroimaging to predict brain age: insights into typical and atypical development and risk for psychopathology

2020 ◽  
Vol 124 (2) ◽  
pp. 400-403
Author(s):  
Carmela Díaz-Arteche ◽  
Divyangana Rakesh
Keyword(s):  
Learning Algorithm ◽  
Brain Maturation ◽  
Future Research ◽  
Childhood And Adolescence ◽  
Brain Structure And Function ◽  
Atypical Development ◽  
And Function ◽  
Brain Age ◽  
The Brain ◽  
Age Prediction

Childhood and adolescence are characterized by complex patterns of changes in brain structure and function. Recently, Truelove-Hill et al. (Truelove-Hill M, Erus G, Bashyam V, Varol E, Sako C, Gur RC, Gur RE, Koutsouleris N, Zhuo C, Fan Y, Wolf DH, Satterthwaite TD, Davatzikos C. J Neurosci 40: 1265–1275, 2020) used a novel machine learning algorithm to capture the subtle nuances of brain maturation during adolescence in two indices based on predicted brain age. In this article, we present an overview of the brain age prediction model used, provide further insight into the utility of this multimodal index to explore typical and atypical development, and discuss avenues for future research.

scholarly journals critical role of astrogenesis and neurodevelopment in Fragile X Syndrome and Rett Syndrome

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
John Paul Oliveria ◽  
Zhuo Jun Li
Keyword(s):  
Fragile X Syndrome ◽  
Rett Syndrome ◽  
Fragile X ◽  
Critical Role ◽  
Notch Pathway ◽  
Janus Kinase ◽  
Future Research ◽  
Genetic Mutations ◽  
And Function ◽  
The Brain

Astrocytes play an important role in the development of functional neural circuits in the brain. They are responsible for coordinating synapse formation and function, axon guidance, and ensuring neuronal survival. Normal astrogenesis begins during late gestation. Neural stem cells (NSCs) become primarily gliogenic and differentiate to become astrocyte precursors. Through local proliferation and functional maturation, the precursors develop into mature astrocytes, which can either be fibrous or protoplasmic. Astrogenesis is regulated by both cell intrinsic programs and cell extrinsic cues. Intrinsic chromatin changes, such as demethylation of astrocyte-specific genes, allows the NSCs to become responsive to astrocyte-inducing exogenous cues. These cues involve a collaboration of multiple pathways, namely the Notch pathway, the bone morphogenetic protein (BMP) signaling pathway, interleukin-6 (IL-6) signaling, and the Janus Kinase/Signal Transducer and Activator of Transcription (JAK-STAT) pathway. Together, they allow for normal astrogenesis to occur. However, disruption to these pathways lead to abnormal astrocyte development and results in pathologies such as the Fragile X Syndrome (FXS) and Rett Syndrome (RS). Both neurodevelopmental disorders are a result of genetic mutations that causes either transcriptional silence or transcriptional activation at inappropriate stages during development. These genetic mutations result in depressed astrocyte function in FXS, and the overexcitement of astrocytes in RS. The current hypothesis under investigation is that altered gene transcription during neurodevelopment disrupts astrogenesis, and subsequently, the behavior and function of mature astrocytes in the brain. Future research should focus on understanding the timing of the transition from neurogenesis to astrogenesis and identifying astrocyte-specific markers that are critical to its function in neurodevelopment.

scholarly journals Neurolinguistics: Structure, Function, and Connectivity in the Bilingual Brain

2016 ◽  
Vol 2016 ◽  
pp. 1-22 ◽  
Author(s):  
Becky Wong ◽  
Bin Yin ◽  
Beth O’Brien
Keyword(s):  
Neural Network ◽  
Language Processing ◽  
Developmental Psychology ◽  
Theoretical Models ◽  
Future Research ◽  
Universal Language ◽  
And Function ◽  
The Impact ◽  
The Brain ◽  
Neuroimaging Techniques

Advances in neuroimaging techniques and analytic methods have led to a proliferation of studies investigating the impact of bilingualism on the cognitive and brain systems in humans. Lately, these findings have attracted much interest and debate in the field, leading to a number of recent commentaries and reviews. Here, we contribute to the ongoing discussion by compiling and interpreting the plethora of findings that relate to the structural, functional, and connective changes in the brain that ensue from bilingualism. In doing so, we integrate theoretical models and empirical findings from linguistics, cognitive/developmental psychology, and neuroscience to examine the following issues: (1) whether the language neural network is different for first (dominant) versus second (nondominant) language processing; (2) the effects of bilinguals’ executive functioning on the structure and function of the “universal” language neural network; (3) the differential effects of bilingualism on phonological, lexical-semantic, and syntactic aspects of language processing on the brain; and (4) the effects of age of acquisition and proficiency of the user’s second language in the bilingual brain, and how these have implications for future research in neurolinguistics.

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