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1.
Physiol Rev ; 98(4): 2349-2380, 2018 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-30109817

RESUMEN

A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.


Asunto(s)
Encéfalo/fisiología , Enfermedades Metabólicas/fisiopatología , Reproducción/fisiología , Animales , Homeostasis/fisiología , Humanos
2.
Horm Behav ; 143: 105195, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35580373

RESUMEN

Thermoregulation is the physiological process by which an animal regulates body temperature in response to its environment. It is known that galanin, a neuropeptide widely distributed throughout the central nervous system and secreted by the gut, plays a role in thermoregulatory behaviors and metabolism. We tested the ability of the novel neuropeptide spexin, which shares sequence homology to galanin, to regulate these functions in female mice. Supraphysiological levels of spexin in C57BL/6 mice did not lead to weight loss after 50 days of treatment. Behavioral analysis of long-term spexin treatment showed it decreased anxiety and increased thermoregulatory nest building, which was not observed when mice were housed at thermoneutral temperatures. Treatment also disrupted the thermogenic profile of brown and white adipose tissue, decreasing mRNA expression of Ucp1 in BAT and immunodetection of ß3-adrenergic receptors in gWAT. Our results reveal novel functions for spexin as a modulator of thermoregulatory behaviors and adipose tissue metabolism.


Asunto(s)
Tejido Adiposo Pardo , Galanina , Tejido Adiposo/metabolismo , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Animales , Regulación de la Temperatura Corporal , Femenino , Galanina/metabolismo , Ratones , Ratones Endogámicos C57BL , Termogénesis/genética , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
3.
PLoS Biol ; 17(3): e3000189, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30893295

RESUMEN

Insulin resistance and obesity are associated with reduced gonadotropin-releasing hormone (GnRH) release and infertility. Mice that lack insulin receptors (IRs) throughout development in both neuronal and non-neuronal brain cells are known to exhibit subfertility due to hypogonadotropic hypogonadism. However, attempts to recapitulate this phenotype by targeting specific neurons have failed. To determine whether astrocytic insulin sensing plays a role in the regulation of fertility, we generated mice lacking IRs in astrocytes (astrocyte-specific insulin receptor deletion [IRKOGFAP] mice). IRKOGFAP males and females showed a delay in balanopreputial separation or vaginal opening and first estrous, respectively. In adulthood, IRKOGFAP female mice also exhibited longer, irregular estrus cycles, decreased pregnancy rates, and reduced litter sizes. IRKOGFAP mice show normal sexual behavior but hypothalamic-pituitary-gonadotropin (HPG) axis dysregulation, likely explaining their low fecundity. Histological examination of testes and ovaries showed impaired spermatogenesis and ovarian follicle maturation. Finally, reduced prostaglandin E synthase 2 (PGES2) levels were found in astrocytes isolated from these mice, suggesting a mechanism for low GnRH/luteinizing hormone (LH) secretion. These findings demonstrate that insulin sensing by astrocytes is indispensable for the function of the reproductive axis. Additional work is needed to elucidate the role of astrocytes in the maturation of hypothalamic reproductive circuits.


Asunto(s)
Astrocitos/metabolismo , Receptor de Insulina/metabolismo , Animales , Femenino , Hormona Liberadora de Gonadotropina/metabolismo , Hormona Luteinizante/metabolismo , Masculino , Ratones , Prostaglandina-E Sintasas/metabolismo , Pubertad Tardía/metabolismo
4.
J Biol Chem ; 291(21): 11124-32, 2016 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-27002145

RESUMEN

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes hepatic insulin clearance. Consistently, mice with null mutation of Ceacam1 (Cc1(-/-)) exhibit impaired insulin clearance with increased lipid production in liver and redistribution to white adipose tissue, leading to visceral obesity at 2 months of age. When the mutation is propagated on the C57/BL6J genetic background, total fat mass rises significantly with age, and glucose intolerance and systemic insulin resistance develop at 6 months of age. This study was carried out to determine the mechanisms underlying the marked increase in total fat mass in 6-month-old mutants. Indirect calorimetry analysis showed that Cc1(-/-) mice develop hyperphagia and a significant reduction in physical activity, in particular in the early hours of the dark cycle, during which energy expenditure is only slightly lower than in wild-type mice. They also exhibit increased triglyceride accumulation in skeletal muscle, due in part to incomplete fatty acid ß-oxidation. Mechanistically, hypothalamic leptin signaling is reduced, as demonstrated by blunted STAT3 phosphorylation in coronal sections in response to an intracerebral ventricular injection of leptin. Hypothalamic fatty-acid synthase activity is also elevated in the mutants. Together, the data show that the increase in total fat mass in Cc1(-/-) mice is mainly attributed to hyperphagia and reduced spontaneous physical activity. Although the contribution of the loss of CEACAM1 from anorexigenic proopiomelanocortin neurons in the arcuate nucleus is unclear, leptin resistance and elevated hypothalamic fatty-acid synthase activity could underlie altered energy balance in these mice.


Asunto(s)
Antígeno Carcinoembrionario/genética , Antígeno Carcinoembrionario/metabolismo , Leptina/metabolismo , Obesidad/etiología , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Moléculas de Adhesión Celular/deficiencia , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Metabolismo Energético , Ácidos Grasos/metabolismo , Eliminación de Gen , Hiperfagia/etiología , Hiperfagia/genética , Hiperfagia/metabolismo , Hipotálamo/metabolismo , Resistencia a la Insulina , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Esquelético/metabolismo , Mutación , Obesidad/genética , Obesidad/metabolismo , Proopiomelanocortina/metabolismo , Transducción de Señal , Triglicéridos/metabolismo
5.
Neuroendocrinology ; 104(4): 330-346, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-27728914

RESUMEN

Obesity is increasing in prevalence across all sectors of society, and with it a constellation of associated ailments including hypertension, type 2 diabetes, and eating disorders. The melanocortin system is a critical neural system underlying the control of body weight and other functions. Deficits in the melanocortin system may promote or exacerbate the comorbidities of obesity. This system has therefore generated great interest as a potential target for treatment of obesity. However, drugs targeting melanocortin receptors are plagued by problematic side effects, including undesirable increases in sympathetic nervous system activity, heart rate, and blood pressure. Circumnavigating this roadblock will require a clearer picture of the precise neural circuits that mediate the functions of melanocortins. Recent, novel experimental approaches have significantly advanced our understanding of these pathways. We here review the latest advances in our understanding of the role of melanocortins in food intake, reward pathways, blood pressure, glucose control, and energy expenditure. The evidence suggests that downstream melanocortin-responsive circuits responsible for different physiological actions do diverge. Ultimately, a more complete understanding of melanocortin pathways and their myriad roles should allow treatments tailored to the mix of metabolic disorders in the individual patient.


Asunto(s)
Melanocortinas/fisiología , Enfermedades Metabólicas/fisiopatología , Glucemia/fisiología , Presión Sanguínea/fisiología , Ingestión de Alimentos/fisiología , Metabolismo Energético/fisiología , Humanos , Vías Nerviosas/fisiología , Vías Nerviosas/fisiopatología , Recompensa
6.
Gynecol Endocrinol ; 33(6): 433-437, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28277126

RESUMEN

Impaired ovarian follicle development, the hallmark of polycystic ovarian syndrome (PCOS), is believed to be due to the changes in expression of related genes such as follistatin (FST). Expression of FST gene and methylation level of its promoter in theca cells from adult female rats, prenatally exposed to androgen excess, during different phases of the estrus cycle was determined and compared with controls. Eight pregnant Wistar rats (experimental group) were treated by subcutaneous injection of 5 mg free testosterone on day 20 of pregnancy, while controls (n = 8) received 500 ml solvent. Based on observed vaginal smear, adult female offspring of mothers were divided into three groups. Levels of serum steroidogenic sexual hormones and gonadotropins, expression and promoter methylation of the FST gene were measured using ELISA, cyber-green real-time PCR and bisulfite sequence PCR (BSP), respectively. Compared to controls, the relative expression of FST gene in the treated group decreased overall by 0.85 fold; despite significant changes in different phases, but no significant differences in methylation of FST promoter. Our results reveal that manifestation of PCOS-like phenotype following prenatal exposure to excess androgen is associated with irregularity in expression of the FST gene during the estrus cycle.


Asunto(s)
Folistatina/metabolismo , Síndrome del Ovario Poliquístico/etiología , Efectos Tardíos de la Exposición Prenatal , Animales , Ciclo Estral , Femenino , Expresión Génica , Embarazo , Distribución Aleatoria , Ratas Wistar , Testosterona , Virilismo
7.
J Biol Chem ; 289(25): 17885-94, 2014 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-24817119

RESUMEN

Glucocorticoids (GCs) are known inhibitors of proliferation and are commonly prescribed to cancer patients to inhibit tumor growth and induce apoptosis via the glucocorticoid receptor (GR). Because of alternative splicing, the GR exists as two isoforms, GRα and GRß. The growth inhibitory actions of GCs are mediated via GRα, a hormone-induced transcription factor. The GRß isoform, however, lacks helix 12 of the ligand-binding domain and cannot bind GCs. While we have previously shown that GRß mRNA is responsive to insulin, the role of GRß in insulin signaling and growth pathways is unknown. In the present study, we show that GRß suppresses PTEN expression, leading to enhanced insulin-stimulated growth. These characteristics were independent of the inhibitory qualities that have been reported for GRß on GRα. Additionally, we found that GRß increased phosphorylation of Akt basally, which was further amplified following insulin treatment. In particular, GRß specifically targets Akt1 in growth pathways. Our results demonstrate that the GRß/Akt1 axis is a major player in insulin-stimulated growth.


Asunto(s)
Regulación Enzimológica de la Expresión Génica/fisiología , Insulina/metabolismo , Fosfohidrolasa PTEN/biosíntesis , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores de Glucocorticoides/metabolismo , Transducción de Señal/fisiología , Células 3T3-L1 , Animales , Insulina/genética , Ratones , Fosfohidrolasa PTEN/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Estructura Secundaria de Proteína , Proteínas Proto-Oncogénicas c-akt/genética , Receptores de Glucocorticoides/genética
8.
bioRxiv ; 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-39005405

RESUMEN

Objective: Kisspeptin, encoded by the Kiss1 gene, ties puberty and fertility to energy status; however, the metabolic factors that control Kiss1-expressing cells need to be clarified. Methods: To evaluate the impact of IGF-1 on the metabolic and reproductive functions of kisspeptin producing cells, we created mice with IGF-1 receptor deletion driven by the Kiss1 promoter (IGF1RKiss1 mice). Previous studies have shown IGF-1 and insulin can bind to each other's receptor, permitting IGF-1 signaling in the absence of IGF1R. Therefore, we also generated mice with simultaneous deletion of the IGF1R and insulin receptor (IR) in Kiss1-expressing cells (IGF1R/IRKiss1 mice). Results: Loss of IGF1R in Kiss1 cells caused stunted body length. In addition, female IGF1RKiss1 mice displayed lower body weight and food intake plus higher energy expenditure and physical activity. This phenotype was linked to higher proopiomelanocortin (POMC) expression and heightened brown adipose tissue (BAT) thermogenesis. Male IGF1RKiss1 mice had mild changes in metabolic functions. Moreover, IGF1RKiss1 mice of both sexes experienced delayed puberty. Notably, male IGF1RKiss1 mice had impaired adulthood fertility accompanied by lower gonadotropin and testosterone levels. Thus, IGF1R in Kiss1-expressing cells impacts metabolism and reproduction in a sex-specific manner. IGF1R/IRKiss1 mice had higher fat mass and glucose intolerance, suggesting IGF1R and IR in Kiss1-expressing cells together regulate body composition and glucose homeostasis. Conclusions: Overall, our study shows that IGF1R and IR in Kiss1 have cooperative roles in body length, metabolism, and reproduction.

9.
Neurosci Biobehav Rev ; 157: 105523, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38142983

RESUMEN

The circadian rhythm affects multiple physiological processes, and disruption of the circadian system can be involved in a range of disease-related pathways. The genetic underpinnings of the circadian rhythm have been well-studied in model organisms. Significant progress has been made in understanding how clock genes affect the physiological functions of the nervous system. In addition, circadian timing is becoming a key factor in improving drug efficacy and reducing drug toxicity. The circadian biology of the target cell determines how the organ responds to the drug at a specific time of day, thus regulating pharmacodynamics. The current review brings together recent advances that have begun to unravel the molecular mechanisms of how the circadian clock affects neurophysiological and behavioral processes associated with human brain diseases. We start with a brief description of how the ubiquitous circadian rhythms are regulated at the genetic, cellular, and neural circuit levels, based on knowledge derived from extensive research on model organisms. We then summarize the latest findings from genetic studies of human brain disorders, focusing on the role of human clock gene variants in these diseases. Lastly, we discuss the impact of common dietary factors and medications on human circadian rhythms and advocate for a broader application of the concept of chronomedicine.


Asunto(s)
Relojes Circadianos , Neurociencias , Humanos , Neurofisiología , Ritmo Circadiano/genética , Relojes Circadianos/genética
10.
Fitoterapia ; 176: 106011, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38740344

RESUMEN

Flavonoids derived from plants offer a broad spectrum of therapeutic potential for addressing metabolic syndrome, particularly diabetes mellitus (DM), a prevalent non-communicable disease. Hyperglycemia in DM is a known risk factor for cardiovascular diseases (CVDs), which substantially impact global mortality rates. This review examines the potential effects of naringin, a citrus flavonoid, on both DM and its associated cardiovascular complications, including conditions like diabetic cardiomyopathy. The safety profile of naringin is summarized based on various pre-clinical studies. The data for this review was gathered from diverse electronic databases, including Medline, PubMed, ScienceDirect, SpringerLink, Google Scholar, and Emerald Insight. Multiple pre-clinical studies have demonstrated that naringin exerts hypoglycemic and cardioprotective effects by targeting various vascular mechanisms. Specifically, research indicates that naringin down-regulates the renin-angiotensin and oxidative stress systems while concurrently upregulating ß-cell and immune system functions. Clinical trial outcomes also support the therapeutic potential of naringin in managing hyperglycemic states and associated cardiovascular issues. Moreover, toxicity studies have confirmed the safety of naringin in animal models, suggesting its potential for safe administration in humans. In conclusion, naringin emerges as a promising natural candidate for both antidiabetic and cardioprotective purposes, offering potential improvements in health outcomes. While naringin presents a new avenue for therapies targeting DM and CVDs, additional controlled and long-term clinical trials are necessary to validate its efficacy and safety for human use.


Asunto(s)
Cardiotónicos , Flavanonas , Hipoglucemiantes , Flavanonas/farmacología , Flavanonas/uso terapéutico , Humanos , Animales , Cardiotónicos/farmacología , Cardiotónicos/uso terapéutico , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Diabetes Mellitus/tratamiento farmacológico , Enfermedades Cardiovasculares/tratamiento farmacológico , Cardiomiopatías Diabéticas/tratamiento farmacológico , Cardiomiopatías Diabéticas/prevención & control , Estrés Oxidativo/efectos de los fármacos , Sistema Renina-Angiotensina/efectos de los fármacos
11.
Clin Obes ; : e12687, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38965765

RESUMEN

Polycyclic aromatic hydrocarbons (PAHs) are naturally occurring environmental pollutants that may contribute to obesity in the adult population. To investigate the relationship between the urinary concentrations of PAH metabolites and adult obesity among the US population, the National Health and Nutritional Examination Survey (NHANES, 2003-2016) was used as a data source for this study. As many as 4464 participants in the NHANES 2003-2016 were included in the final analyses. We used logistic regression to look at the link between urinary PAH metabolites and obesity, using odds ratios (ORs) and 95% confidence intervals (CIs). The study sample comprised 4464 individuals aged ≥18 years, 2199 were male and 2265 were female. The study characteristics for four different quartiles were analyzed, and the average ages of the four urinary PAH quartiles were 49.61 ± 20.01, 46.63 ± 20.33, 44.28 ± 19.19, and 43.27 ± 17.68 years, respectively. In the quartile analysis of all participants, the third quartile was significantly associated with an increased prevalence of obesity (OR = 1.33, 95% CI = 1.12-1.59) with p-values <.05. In addition, females, but not males, had a strong link between the second, third, and fourth quartiles of urinary PAH and a higher risk of obesity (OR = 1.27, 95% CI = 1.00-1.61; OR = 1.52, 95% CI = 1.19-1.94; and OR = 1.39, 95% CI = 1.09-1.78). In conclusion, the study observed that urinary PAH metabolites were associated with the prevalence of obesity among the US population.

12.
Nat Rev Endocrinol ; 20(2): 111-123, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38049643

RESUMEN

An individual's nutritional status has a powerful effect on sexual maturation. Puberty onset is delayed in response to chronic energy insufficiency and is advanced under energy abundance. The consequences of altered pubertal timing for human health are profound. Late puberty increases the chances of cardiometabolic, musculoskeletal and neurocognitive disorders, whereas early puberty is associated with increased risks of adult obesity, type 2 diabetes mellitus, cardiovascular diseases and various cancers, such as breast, endometrial and prostate cancer. Kennedy and Mitra's trailblazing studies, published in 1963 and using experimental models, were the first to demonstrate that nutrition is a key factor in puberty onset. Building on this work, the field has advanced substantially in the past decade, which is largely due to the impressive development of molecular tools for experimentation and population genetics. In this Review, we discuss the latest advances in basic and translational sciences underlying the nutritional and metabolic control of pubertal development, with a focus on perspectives and future directions.


Asunto(s)
Diabetes Mellitus Tipo 2 , Neoplasias de la Próstata , Masculino , Adulto , Humanos , Diabetes Mellitus Tipo 2/genética , Pubertad/fisiología , Maduración Sexual/fisiología , Obesidad/genética
13.
Inflammation ; 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38289578

RESUMEN

Methotrexate (MTX)-induced intestinal mucositis (IM) is a common side effect in cancer treatment that impairs the immune system and gut microbes, resulting in loss of mucosal integrity and gut barrier dysfunction. The quality of life and outcomes of treatment are compromised by IM. The present study was designed to investigate the mucoprotective potential of the benzimidazole derivative N-{4-[2-(4-methoxyphenyl)-1H-benzimidazole-1-sulfonyl] phenyl} acetamide (B8) on MTX-induced IM in mice. IM was induced by a single dose of MTX in mice and assessed by physical manifestations as well as biochemical, oxidative, histological, and inflammatory parameters. B8 (1, 3, 9 mg/kg) significantly reduced diarrhea score, mitigated weight loss, increased feed intake and, survival rate in a dose-dependent manner. Notably, B8 exhibited a mucoprotective effect evident through the mitigation of villus atrophy, crypt hypoplasia, diminished crypt mitotic figures, mucin depletion, and oxidative stress markers (GSH, SOD, MDA, and catalase concentration). Gene expression analysis revealed that B8 downregulated the mRNA expression of tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), IL-1ß, and nuclear factor-κB (NF-κB) and concurrently upregulated IL-10 expression in contrast to the MTX group. Further, B8 significantly improved the luminal microflora profile by augmenting the growth of Lactobacillus spp. and reducing the number of pathogenic bacteria (E. coli). Additionally, the enzyme-linked immunoassay showed that B8 decreased the levels of pro-inflammatory cytokines. Our findings suggest that B8 had mucoprotective effects against MTX-induced IM and could be used as an adjunct in chemotherapy to deter this side effect.

14.
BMC Cell Biol ; 14: 39, 2013 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-24053798

RESUMEN

BACKGROUND: Differentiation and fusion of skeletal muscle myoblasts into multi-nucleated myotubes is required for neonatal development and regeneration in adult skeletal muscle. Herein, we report novel findings that protein kinase C theta (PKCθ) regulates myoblast differentiation via phosphorylation of insulin receptor substrate-1 and ERK1/2. RESULTS: In this study, PKCθ knockdown (PKCθshRNA) myotubes had reduced inhibitory insulin receptor substrate-1 ser1095 phosphorylation, enhanced myoblast differentiation and cell fusion, and increased rates of protein synthesis as determined by [3H] phenylalanine incorporation. Phosphorylation of insulin receptor substrate-1 ser632/635 and extracellular signal-regulated kinase1/2 (ERK1/2) was increased in PKCθshRNA cells, with no change in ERK5 phosphorylation, highlighting a PKCθ-regulated myogenic pathway. Inhibition of PI3-kinase prevented cell differentiation and fusion in control cells, which was attenuated in PKCθshRNA cells. Thus, with reduced PKCθ, differentiation and fusion occur in the absence of PI3-kinase activity. Inhibition of the ERK kinase, MEK1/2, impaired differentiation and cell fusion in control cells. Differentiation was preserved in PKCθshRNA cells treated with a MEK1/2 inhibitor, although cell fusion was blunted, indicating PKCθ regulates differentiation via IRS1 and ERK1/2, and this occurs independently of MEK1/2 activation. CONCLUSION: Cellular signaling regulating the myogenic program and protein synthesis are complex and intertwined. These studies suggest that PKCθ regulates myogenic and protein synthetic signaling via the modulation of IRS1and ERK1/2 phosphorylation. Myotubes lacking PKCθ had increased rates of protein synthesis and enhanced myotube development despite reduced activation of the canonical anabolic-signaling pathway. Further investigation of PKCθ regulated signaling may reveal important interactions regulating skeletal muscle health in an insulin resistant state.


Asunto(s)
Proteínas Sustrato del Receptor de Insulina/genética , Isoenzimas/genética , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/genética , Desarrollo de Músculos/genética , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/metabolismo , Proteína Quinasa C/genética , Animales , Diferenciación Celular , Fusión Celular , Células Cultivadas , Regulación del Desarrollo de la Expresión Génica , Proteínas Sustrato del Receptor de Insulina/metabolismo , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , MAP Quinasa Quinasa 1/genética , MAP Quinasa Quinasa 1/metabolismo , MAP Quinasa Quinasa 2/genética , MAP Quinasa Quinasa 2/metabolismo , Ratones , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Fibras Musculares Esqueléticas/citología , Mioblastos/citología , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Biosíntesis de Proteínas , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C/metabolismo , Proteína Quinasa C-theta , Inhibidores de Proteínas Quinasas/farmacología , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal
15.
Front Endocrinol (Lausanne) ; 14: 983670, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37033219

RESUMEN

Introduction: Female sexual dysfunction affects approximately 40% of women in the United States, yet few therapeutic options exist for these patients. The melanocortin system is a new treatment target for hypoactive sexual desire disorder (HSDD), but the neuronal pathways involved are unclear. Methods: In this study, the sexual behavior of female MC4R knockout mice lacking melanocortin 4 receptors (MC4Rs) was examined. The mice were then bred to express MC4Rs exclusively on Sim1 neurons (tbMC4RSim1 mice) or on oxytocin neurons (tbMC4ROxt mice) to examine the effect on sexual responsiveness. Results: MC4R knockout mice were found to approach males less and have reduced receptivity to copulation, as indicated by a low lordosis quotient. These changes were independent of body weight. Lordosis behavior was normalized in tbMC4RSim1 mice and improved in tbMC4ROxt mice. In contrast, approach behavior was unchanged in tbMC4RSim1 mice but greatly increased in tbMC4ROxt animals. The changes were independent of melanocortin-driven metabolic effects. Discussion: These results implicate MC4R signaling in Oxt neurons in appetitive behaviors and MC4R signaling in Sim1 neurons in female sexual receptivity, while suggesting melanocortin-driven sexual function does not rely on metabolic neural circuits.


Asunto(s)
Lordosis , Receptor de Melanocortina Tipo 4 , Masculino , Ratones , Animales , Femenino , Receptor de Melanocortina Tipo 4/genética , Receptor de Melanocortina Tipo 4/metabolismo , Lordosis/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Neuronas/metabolismo , Ratones Noqueados , Melanocortinas/metabolismo , Proteínas Represoras , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo
16.
J Clin Invest ; 118(5): 1796-805, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18382766

RESUMEN

Normal food intake and body weight homeostasis require the direct action of leptin on hypothalamic proopiomelanocortin (POMC) neurons. It has been proposed that leptin action requires PI3K activity. We therefore assessed the contribution of PI3K signaling to leptin's effects on POMC neurons and organismal energy balance. Leptin caused a rapid depolarization of POMC neurons and an increase in action potential frequency in patch-clamp recordings of hypothalamic slices. Pharmacologic inhibition of PI3K prevented this depolarization and increased POMC firing rate, indicating a PI3K-dependent mechanism of leptin action. Mice with genetically disrupted PI3K signaling in POMC cells failed to undergo POMC depolarization or increased firing frequency in response to leptin. Insulin's ability to hyperpolarize POMC neurons was also abolished in these mice. Moreover, targeted disruption of PI3K blunted the suppression of feeding elicited by central leptin administration. Despite these differences, mice with impaired PI3K signaling in POMC neurons exhibited normal long-term body weight regulation. Collectively, these results suggest that PI3K signaling in POMC neurons is essential for leptin-induced activation and insulin-induced inhibition of POMC cells and for the acute suppression of food intake elicited by leptin, but is not a major contributor to the regulation of long-term organismal energy homeostasis.


Asunto(s)
Hipotálamo/citología , Leptina/metabolismo , Neuronas/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proopiomelanocortina/metabolismo , Transducción de Señal/fisiología , Animales , Peso Corporal , Ingestión de Alimentos , Metabolismo Energético , Homeostasis , Humanos , Ratones , Ratones Noqueados , Neuronas/citología , Técnicas de Placa-Clamp
17.
J Neuroendocrinol ; 33(4): e12930, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33523515

RESUMEN

Infertility associated with insulin resistance is characterised by abnormal hormone secretion by the hypothalamus, pituitary gland and gonads. These endocrine tissues can maintain insulin sensitivity even when tissues such as the muscle and liver become insulin-resistant, resulting in excessive insulin stimulation as hyperinsulinaemia develops. Experiments conducted to determine the role of neuronal insulin signalling in fertility were unable to recapitulate early findings of hypogonadotrophic hypogonadism in mice lacking insulin receptors throughout the brain. Rather, it was eventually shown that astrocytes critically mediate the effects of insulin on puberty timing and adult reproductive function. However, specific roles for neurones and gonadotrophs have been revealed under conditions of hyperinsulinaemia and by ablation of insulin and leptin receptors. The collective picture is one of multiple insulin-responsive inputs to gonadotrophin releasing hormone neurones, with astrocytes being the most important player.

18.
Mol Cell Endocrinol ; 518: 110996, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-32860862

RESUMEN

The hypothalamic-pituitary-gonadal axis is controlled by gonadotropin-releasing hormone (GnRH) released by the hypothalamus. Disruption of this system leads to impaired reproductive maturation and function, a condition known as hypogonadotropic hypogonadism (HH). Most studies to date have focused on genetic causes of HH that impact neuronal development and function. However, variants may also impact the functioning of non-neuronal cells known as glia. Glial cells make up 50% of brain cells of humans, primates, and rodents. They include radial glial cells, microglia, astrocytes, tanycytes, oligodendrocytes, and oligodendrocyte precursor cells. Many of these cells influence the hypothalamic neuroendocrine system controlling fertility. Indeed, glia regulate GnRH neuronal activity and secretion, acting both at their cell bodies and their nerve endings. Recent work has also made clear that these interactions are an essential aspect of how the HPG axis integrates endocrine, metabolic, and environmental signals to control fertility. Recognition of the clinical importance of interactions between glia and the GnRH network may pave the way for the development of new treatment strategies for dysfunctions of puberty and adult fertility.


Asunto(s)
Células Endocrinas/fisiología , Hipogonadismo/etiología , Animales , Hormona Liberadora de Gonadotropina/metabolismo , Humanos , Hipogonadismo/metabolismo , Hipotálamo/metabolismo , Neuronas/fisiología , Sistemas Neurosecretores/metabolismo , Sistemas Neurosecretores/fisiología , Reproducción/fisiología
19.
Endocrinology ; 161(2)2020 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-31912132

RESUMEN

Recent work shows that gut microbial dysbiosis contributes to the risk of obesity in children whose mothers consume a high-fat diet (HFD) during both gestation and lactation or during gestation alone. Obesity predisposes children to developing precocious puberty. However, to date, no study has examined how maternal HFD (MHFD) during lactation regulates the gut microbiota (GM), pubertal timing, and fertility of offspring. Here, we found that MHFD during lactation markedly altered the GM of offspring. The pups developed juvenile obesity, early puberty, irregular estrous cycles, and signs of disrupted glucose metabolism. Remarkably, permitting coprophagia between MHFD and maternal normal chow offspring successfully reversed the GM changes as well as early puberty and insulin insensitivity. Our data suggest that microbial reconstitution may prevent or treat early puberty associated with insulin resistance.


Asunto(s)
Microbioma Gastrointestinal , Lactancia , Exposición Materna , Obesidad Infantil/microbiología , Pubertad Precoz/microbiología , Animales , Dieta Alta en Grasa , Femenino , Resistencia a la Insulina , Ratones Endogámicos C57BL , Obesidad Infantil/complicaciones
20.
Hypertension ; 75(6): 1386-1396, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32336227

RESUMEN

For over 100 years, essential hypertension has been researched from different perspectives ranging from genetics, physiology, and immunology to more recent ones encompassing microbiology (microbiota) as a previously underappreciated field of study contributing to the cause of hypertension. Each field of study in isolation has uniquely contributed to a variety of underlying mechanisms of blood pressure regulation. Even so, clinical management of essential hypertension has remained somewhat static. We, therefore, asked if there are any converging lines of evidence from these individual fields that could be amenable for a better clinical prognosis. Accordingly, here we present converging evidence which support the view that metabolic dysfunction underlies essential hypertension.


Asunto(s)
Presión Sanguínea/fisiología , Manejo de la Enfermedad , Hipertensión Esencial , Metabolismo/fisiología , Hipertensión Esencial/inmunología , Hipertensión Esencial/metabolismo , Hipertensión Esencial/microbiología , Hipertensión Esencial/fisiopatología , Humanos , Microbiota
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