scholarly journals The roles of melanin-concentrating hormone in energy balance and reproductive function: are they connected?

Reproduction ◽  
2013 ◽  
Vol 146 (5) ◽  
pp. R141-R150 ◽  
Author(s):  
Jane Naufahu ◽  
Adam D Cunliffe ◽  
Joanne F Murray
Keyword(s):  
Energy Balance ◽  
Reproductive Function ◽  
Discrete Systems ◽  
Diet Induced Obesity ◽  
Published Evidence ◽  
Reproductive Axis ◽  
Literature Evidence ◽  
Complex Control System ◽  
Melanin Concentrating Hormone

Melanin-concentrating hormone (MCH) is an anabolic neuropeptide with multiple and diverse physiological functions including a key role in energy homoeostasis. Rodent studies have shown that the ablation of functional MCH results in a lean phenotype, increased energy expenditure and resistance to diet-induced obesity. These findings have generated interest among pharmaceutical companies vigilant for potential anti-obesity agents. Nutritional status affects reproductive physiology and behaviours, thereby optimising reproductive success and the ability to meet energetic demands. This complex control system entails the integration of direct or indirect peripheral stimuli with central effector systems and involves numerous mediators. A role for MCH in the reproductive axis has emerged, giving rise to the premise that MCH may serve as an integratory mediator between those discrete systems that regulate energy balance and reproductive function. Hence, this review focuses on published evidence concerning i) the role of MCH in energy homoeostasis and ii) the regulatory role of MCH in the reproductive axis. The question as to whether the MCH system mediates the integration of energy homoeostasis with the neuroendocrine reproductive axis and, if so, by what means has received limited coverage in the literature; evidence to date and current theories are summarised herein.

scholarly journals Expression of Melanin-Concentrating Hormone Receptor 2 Protects Against Diet-Induced Obesity in Male Mice

Endocrinology ◽  
2014 ◽  
Vol 155 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Melissa J. S. Chee ◽  
Pavlos Pissios ◽  
Deepthi Prasad ◽  
Eleftheria Maratos-Flier
Keyword(s):  
Energy Balance ◽  
High Fat Diet ◽  
Potential Role ◽  
Early Gene ◽  
Wild Type ◽  
Diet Induced Obesity ◽  
Melanin Concentrating Hormone ◽  
The Central Nervous System ◽  
Insight Into

Melanin-concentrating hormone (MCH) is an orexigenic neuropeptide that is a ligand for two subtypes of MCH receptors, MCHR1 and MCHR2. MCHR1 is universally expressed in mammals ranging from rodents to humans, but the expression of MCHR2 is substantially restricted. In mammals, MCHR2 has been defined in primates as well as other species such as cats and dogs but is not seen in rodents. Although the role of MCHR1 in mediating the actions of MCH on energy balance is clearly defined using mouse models, the role of MCHR2 is harder to characterize because of its limited expression. To determine any potential role of MCHR2 in energy balance, we generated a transgenic MCHR1R2 mouse model, where human MCHR2 is coexpressed in MCHR1-expressing neurons. As shown previously, control wild-type mice expressing only native MCHR1 developed diet-induced obesity when fed a high-fat diet. In contrast, MCHR1R2 mice had lower food intake, leading to their resistance to diet-induced obesity. Furthermore, we showed that MCH action is altered in MCHR1R2 mice. MCH treatment in wild-type mice inhibited the activation of the immediate-early gene c-fos, and coexpression of MCHR2 reduced the inhibitory actions of MCHR1 on this pathway. In conclusion, we developed an experimental animal model that can provide insight into the action of MCHR2 in the central nervous system and suggest that some actions of MCHR2 oppose the endogenous actions of MCHR1.

scholarly journals Emerging roles of epigenetics in the control of reproductive function: Focus on central neuroendocrine mechanisms

2021 ◽  
Author(s):  
Maria Jesus Vazquez ◽  
Silvia Daza-Dueñas ◽  
Manuel Tena-Sempere
Keyword(s):  
Perfect Match ◽  
Reproductive Function ◽  
Reproductive Capacity ◽  
Special Focus ◽  
Epigenetic Mechanisms ◽  
Reproductive Axis ◽  
Neuroendocrine Mechanisms ◽  
Essential Function ◽  
And Function

Abstract Reproduction is an essential function for perpetuation of the species. As such, it is controlled by sophisticated regulatory mechanisms, which allow a perfect match between environmental conditions and internal cues, to ensure adequate pubertal maturation and achievement of reproductive capacity. Besides classical genetic regulatory events, mounting evidence has documented that different epigenetic mechanisms operate at different levels of the reproductive axis to finely tune the development and function of this complex neuroendocrine system along the lifespan. In this mini-review, we will summarize recent evidence on the role of epigenetics in the control of reproduction, with special focus on the modulation of the central components of this axis. Particular attention will be paid to the epigenetic control of puberty and Kiss1 neurons, as major developments have taken place in this domain recently. In addition, the putative role of central epigenetic mechanisms in mediating the influence of nutritional and environmental cues on reproductive function will be also discussed.

scholarly journals Reproduction and energy balance: the integrative role of prolactin

2014 ◽  
Vol 11 (1) ◽  
pp. 5-18 ◽  
Author(s):  
T I Romantsova
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Energy Balance ◽  
Dopamine Agonists ◽  
Reproductive Function ◽  
Breast Development ◽  
Risk Markers ◽  
Physiological Mechanisms ◽  
Metabolic Functions

The physiological mechanisms controlling reproduction are closely linked to energy balance. In the recent years, accumulating evidence suggests that prolactin regulates metabolic functions, besides regulating breast development and stimulating milk formation. Hyperprolactinemia is associated with obesity and treatment with dopamine agonists results in weight loss. We discuss the integrated effects of prolactin in the metabolic control and reproductive function, the role of prolactin in the pathogenesis of obesity. The present review also describes the effects of treatment with cabergoline on body weight and cardiovascular risk markers.

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 Role of GnRH Neurons and Their Neuronal Afferents as Key Integrators between Food Intake Regulatory Signals and the Control of Reproduction

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Juan Roa
Keyword(s):  
Food Intake ◽  
Metabolic Control ◽  
Reproductive Function ◽  
Energy Availability ◽  
Energy Status ◽  
Metabolic Factors ◽  
Metabolic Hormones ◽  
Reproductive Axis ◽  
Metabolic Information

Reproductive function is regulated by a plethora of signals that integrate physiological and environmental information. Among others, metabolic factors are key components of this circuit since they inform about the propitious timing for reproduction depending on energy availability. This information is processed mainly at the hypothalamus that, in turn, modulates gonadotropin release from the pituitary and, thereby, gonadal activity. Metabolic hormones, such as leptin, insulin, and ghrelin, act as indicators of the energy status and convey this information to the reproductive axis regulating its activity. In this review, we will analyse the central mechanisms involved in the integration of this metabolic information and their contribution to the control of the reproductive function. Particular attention will be paid to summarize the participation of GnRH, Kiss1, NPY, and POMC neurons in this process and their possible interactions to contribute to the metabolic control of reproduction.

scholarly journals Kisspeptin and energy balance in reproduction

Reproduction ◽  
2014 ◽  
Vol 147 (3) ◽  
pp. R53-R63 ◽  
Author(s):  
Julie-Ann P De Bond ◽  
Jeremy T Smith
Keyword(s):  
Body Weight ◽  
Energy Balance ◽  
Arcuate Nucleus ◽  
Reproductive Function ◽  
Neuroendocrine Regulation ◽  
Direct Role ◽  
Gnrh Neurons ◽  
The Brain ◽  
Direct Regulator

Kisspeptin is vital for the neuroendocrine regulation of GNRH secretion. Kisspeptin neurons are now recognized as a central pathway responsible for conveying key homeostatic information to GNRH neurons. This pathway is likely to mediate the well-established link between energy balance and reproductive function. Thus, in states of severely altered energy balance (either negative or positive), fertility is compromised, as isKiss1expression in the arcuate nucleus. A number of metabolic modulators have been proposed as regulators of kisspeptin neurons including leptin, ghrelin, pro-opiomelanocortin (POMC), and neuropeptide Y (NPY). Whether these regulate kisspeptin neurons directly or indirectly will be discussed. Moreover, whether the stimulatory role of leptin on reproduction is mediated by kisspeptin directly will be questioned. Furthermore, in addition to being expressed in GNRH neurons, the kisspeptin receptor (Kiss1r) is also expressed in other areas of the brain, as well as in the periphery, suggesting alternative roles for kisspeptin signaling outside of reproduction. Interestingly, kisspeptin neurons are anatomically linked to, and can directly excite, anorexigenic POMC neurons and indirectly inhibit orexigenic NPY neurons. Thus, kisspeptin may have a direct role in regulating energy balance. Although data fromKiss1rknockout and WT mice found no differences in body weight, recent data indicate that kisspeptin may still play a role in food intake and glucose homeostasis. Thus, in addition to regulating reproduction, and mediating the effect of energy balance on reproductive function, kisspeptin signaling may also be a direct regulator of metabolism.

scholarly journals Expanding the role of tachykinins in the neuroendocrine control of reproduction

Reproduction ◽  
2017 ◽  
Vol 153 (1) ◽  
pp. R1-R14 ◽  
Author(s):  
Chrysanthi Fergani ◽  
Víctor M Navarro
Keyword(s):  
Reproductive Function ◽  
Neurokinin A ◽  
Alternative Pathways ◽  
Gnrh Secretion ◽  
The Awakening ◽  
Reproductive Axis ◽  
Pharmacological Studies ◽  
Important Pathway ◽  
Kndy Neurons

Reproductive function is driven by the hormonal interplay between the gonads and brain–pituitary axis. Gonadotropin-releasing hormone (GnRH) is released in a pulsatile manner, which is critical for the attainment and maintenance of fertility; however, GnRH neurons lack the ability to directly respond to most regulatory factors, and a hierarchical upstream neuronal network governs its secretion. We and others proposed a model in which Kiss1 neurons in the arcuate nucleus (ARC), called as KNDy neurons, release kisspeptin (a potent GnRH secretagogue) in a pulsatile manner to drive GnRH pulses under the coordinated autosynaptic action of its cotransmitters, the tachykinin neurokinin B (NKB, stimulatory) and dynorphin (inhibitory). Numerous genetic and pharmacological studies support this model; however, additional regulatory mechanisms (upstream of KNDy neurons) and alternative pathways of GnRH secretion (kisspeptin independent) exist, but remain ill defined. In this aspect, attention to other members of the tachykinin family, namely substance P (SP) and neurokinin A (NKA), has recently been rekindled. Even though there are still major gaps in our knowledge about the functional significance of these systems, substantial evidence, as discussed below, is placing tachykinin signaling as an important pathway for the awakening of the reproductive axis and the onset of puberty to physiological GnRH secretion and maintenance of fertility in adulthood.

scholarly journals Adipokines and the Female Reproductive Tract

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Maxime Reverchon ◽  
Christelle Ramé ◽  
Michael Bertoldo ◽  
Joëlle Dupont
Keyword(s):  
Adipose Tissue ◽  
Reproductive Tract ◽  
Polycystic Ovary ◽  
Reproductive Function ◽  
Female Reproductive Tract ◽  
Ovary Syndrome ◽  
Reproductive Axis ◽  
Endocrine Effect ◽  
Hypothalamic Pituitary Axis

It is well known that adipose tissue can influence puberty, sexual maturation, and fertility in different species. Adipose tissue secretes molecules called adipokines which most likely have an endocrine effect on reproductive function. It has been revealed over the last few years that adipokines are functionally implicated at all levels of the reproductive axis including the gonad and hypothalamic-pituitary axis. Many studies have shown the presence and the role of the adipokines and their receptors in the female reproductive tract of different species. These adipokines regulate ovarian steroidogenesis, oocyte maturation, and embryo development. They are also present in the uterus and placenta where they could create a favorable environment for embryonic implantation and play a key role in maternal-fetal metabolism communication and gestation. Reproductive functions are strongly dependent on energy balance, and thereby metabolic abnormalities can lead to the development of some pathophysiologies such as polycystic ovary syndrome (PCOS). Adipokines could be a link between reproduction and energy metabolism and could partly explain some infertility related to obesity or PCOS.

scholarly journals Integrative Control of Energy Balance and Reproduction in Females

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
R. M. Garcia-Garcia
Keyword(s):  
Energy Balance ◽  
Maternal Nutrition ◽  
Strong Association ◽  
Reproductive Function ◽  
Reproductive Capacity ◽  
Dietary Energy ◽  
Gonadotropin Secretion ◽  
Systemic Level ◽  
Reproductive Events

There is a strong association between nutrition and reproduction. Chronic dietary energy deficits as well as energy surpluses can impair reproductive capacity. Metabolic status impacts reproductive function at systemic level, modulating the hypothalamic GnRH neuronal network and/or the pituitary gonadotropin secretion through several hormones and neuropeptides, and at the ovarian level, acting through the regulation of follicle growth and steroidogenesis by means of the growth hormone-IGF-insulin system and local ovarian mediators. In the past years, several hormones and neuropeptides have been emerging as important mediators between energy balance and reproduction. The present review goes over the main sites implicated in the control of energy balance linked to reproductive success and summarizes the most important metabolic and neuroendocrine signals that participate in reproductive events with special emphasis on the role of recently discovered neuroendocrine peptides. Also, a little overview about the effects of maternal nutrition, affecting offspring reproduction, has been presented.

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