scholarly journals Leptin Sensitivity in the Developing Rat Hypothalamus

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 6073-6082 ◽  
Author(s):  
A.-S. Carlo ◽  
M. Pyrski ◽  
C. Loudes ◽  
A. Faivre-Baumann ◽  
J. Epelbaum ◽  
...  
Keyword(s):  
Food Intake ◽  
Neuropeptide Y ◽  
Leptin Receptor ◽  
Primary Cultures ◽  
Cytokine Signaling ◽  
Neuronal Cultures ◽  
Mrna Levels ◽  
Leptin Signaling ◽  
Leptin Sensitivity

In adults, the adipocyte-derived hormone, leptin, regulates food intake and body weight principally via the hypothalamic arcuate nucleus (ARC). During early postnatal development, leptin functions to promote the outgrowth of neuronal projections from the ARC, whereas a selective insensitivity to the effects of leptin on food intake appears to exist. To investigate the mechanisms underlying the inability of leptin to regulate food intake during early development, leptin signaling was analyzed both in vitro using primary cultures of rat embryonic ARC neurones and in vivo by challenging early postnatal rats with leptin. In neuronal cultures, despite the presence of key components of the leptin signaling pathway, no detectable activation of either signal transducer and activator of transcription 3 or the MAPK pathways by leptin was detected. However, leptin down-regulated mRNA levels of proopiomelanocortin and neuropeptide Y and decreased somatostatin secretion. Leptin challenge in vivo at postnatal d (P) 7, P14, P21, and P28 revealed that, in contrast to adult and P28 rats, mRNA levels of neuropeptide Y, proopiomelanocortin, agouti-related peptide and cocaine- and amphetamine-regulated transcript were largely unaffected at P7, P14, and P21. Furthermore, leptin stimulation increased the suppressor of cytokine signaling-3 mRNA levels at P14, P21, and P28 in several hypothalamic nuclei but not at P7, indicating that selective leptin insensitivity in the hypothalamus is coupled to developmental shifts in leptin receptor signaling. Thus, the present study defines the onset of leptin sensitivity in the regulation of energy homeostasis in the developing hypothalamus.

scholarly journals Leptin Signaling in the Hypothalamus during Chronic Central Leptin Infusion

Endocrinology ◽  
2003 ◽  
Vol 144 (9) ◽  
pp. 3789-3798 ◽  
Author(s):  
Rekha Pal ◽  
Abhiram Sahu
Keyword(s):  
Food Intake ◽  
Leptin Receptor ◽  
Binding Activity ◽  
Janus Kinase ◽  
Male Rats ◽  
Leptin Resistance ◽  
Cytokine Signaling ◽  
Mrna Levels ◽  
Leptin Signaling ◽  
Initial Decrease

Abstract Using a rat model of chronic central leptin infusion in which neuropeptide Y neurons develop leptin resistance, we examined whether leptin signal transduction mechanism in the hypothalamus is altered during central leptin infusion. Adult male rats were infused chronically into the lateral cerebroventricle with leptin (160 ng/h) or vehicle via Alzet pumps for 16 d. In the leptin-infused group, the initial decrease in food intake was followed by a recovery to their preleptin levels by d 16, although food intake remained significantly lower than in artificial cerebrospinal fluid controls; and body weight gradually decreased reaching a nadir at d 11 and remained stabilized at lower level thereafter. Phosphorylated leptin receptor and phosphorylated signal transducer and activator of transcription-3 (p-STAT3) remained elevated in association with a sustained elevation in DNA-binding activity of STAT3 in the hypothalamus throughout 16-d period of leptin infusion. However, phosphorylated Janus kinase-2 was increased during the early part of leptin infusion but remained unaltered on d 16. Although hypothalamic suppressors of cytokine signaling-3 (SOCS3) mRNA levels were increased throughout leptin infusion, SOCS3 protein levels were increased only on d 16. This study demonstrates a sustained elevation in hypothalamic leptin receptor signaling through Janus kinase-STAT pathway despite an increased expression of SOCS3 during chronic central leptin infusion. We propose that an alteration in leptin signaling in the hypothalamus through pathways other than STAT3 and/or a defect in downstream of STAT3 signaling may be involved in food intake recovery seen after an initial decrease during chronic central leptin infusion.

scholarly journals Leptin and glucocorticoid signaling pathways in the hypothalamus of female and male fructose-fed rats

2014 ◽  
Vol 66 (2) ◽  
pp. 829-839 ◽  
Author(s):  
Danijela Vojnovic-Milutinovic ◽  
Marina Nikolic ◽  
Jovana Dinic ◽  
Ana Djordjevic ◽  
Natasa Velickovic ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Signaling Pathway ◽  
Leptin Receptor ◽  
Female Rats ◽  
Male Rats ◽  
Cytokine Signaling ◽  
Mrna Levels ◽  
Leptin Sensitivity ◽  
Male And Female Rats ◽  
Glucocorticoid Signaling

Alterations in leptin and glucocorticoid signaling pathways in the hypothalamus of male and female rats subjected to a fructose-enriched diet were studied. The level of expression of the key components of the leptin signaling pathway (neuropeptide Y /NPY/ and suppressor of cytokine signaling 3 /SOCS3/), and the glucocorticoid signaling pathway (glucocorticoid receptor /GR/, 11?-hydroxysteroid dehydrogenase type 1 /11?HSD1/ and hexose-6-phosphate dehydrogenase /H6PDH/) did not differ between fructose-fed rats and control animals of both genders. However, in females, a fructose-enriched diet provoked increases in the adiposity index, plasma leptin and triglyceride concentrations, and displayed a tendency to decrease the leptin receptor (ObRb) protein and mRNA levels. In male rats, the fructose diet caused elevations in plasma non-esterified fatty acids and triglycerides, as well as in both plasma and hypothalamic leptin concentrations. Our results suggest that a fructose-enriched diet can induce hyperleptinemia in both female and male rats, but with a more pronounced effect on hypothalamic leptin sensitivity in females, probably contributing to the observed development of visceral adiposity.

scholarly journals C1q/TNF-related protein 4 restores leptin sensitivity by downregulating NF-κB signaling and microglial activation

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Liu Ye ◽  
Gongwei Jia ◽  
Yuejie Li ◽  
Ying Wang ◽  
Hong Chen ◽  
...  
Keyword(s):  
Food Intake ◽  
Microglial Activation ◽  
Obese Mice ◽  
Related Protein ◽  
Leptin Signaling ◽  
Leptin Sensitivity ◽  
Tnf Α ◽  
Hypothalamic Inflammation ◽  
The Impact

Abstract Objective C1qTNF-related protein 4 (CTRP4) acts in the hypothalamus to modulate food intake in diet-induced obese mice and has been shown to exert an anti-inflammatory effect on macrophages. Since high-fat diet-induced microglial activation and hypothalamic inflammation impair leptin signaling and increase food intake, we aimed to explore the potential connection between the anorexigenic effect of CTRP4 and the suppression of hypothalamic inflammation in mice with DIO. Methods Using an adenovirus-mediated hypothalamic CTRP4 overexpression model, we investigated the impact of CTRP4 on food intake and the hypothalamic leptin signaling pathway in diet-induced obese mice. Furthermore, central and plasma proinflammatory cytokines, including TNF-α and IL-6, were measured by Western blotting and ELISA. Changes in the hypothalamic NF-κB signaling cascade and microglial activation were also examined in vivo. In addition, NF-κB signaling and proinflammatory factors were investigated in BV-2 cells after CTRP4 intervention. Results We found that food intake was decreased, while leptin signaling was significantly improved in mice with DIO after CTRP4 overexpression. Central and peripheral TNF-α and IL-6 levels were reduced by central Ad-CTRP4 administration. Hypothalamic NF-κB signaling and microglial activation were also significantly suppressed in vivo. In addition, NF-κB signaling was inhibited in BV-2 cells following CTRP4 intervention, which was consistent with the decreased production of TNF-α and IL-6. Conclusions Our data indicate that CTRP4 reverses leptin resistance by inhibiting NF-κB-dependent microglial activation and hypothalamic inflammation.

Divergent effects of intracerebroventricular and peripheral leptin administration on feeding and hypothalamic neuropeptide Y in lean and obese (fa/fa) Zucker rats

1999 ◽  
Vol 96 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Simon DRYDEN ◽  
Peter KING ◽  
Lucy PICKAVANCE ◽  
Patrick DOYLE ◽  
Gareth WILLIAMS
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Leptin Receptor ◽  
Zucker Rats ◽  
Mrna Levels ◽  
Zucker Rat ◽  
Direct Effects ◽  
The Central Nervous System

Leptin inhibits feeding and decreases body weight. It may act partly by inhibiting hypothalamic neurons that express neuropeptide Y, a powerful inducer of feeding and obesity. These neuropeptide Y neurons express the Ob-Rb leptin receptor and are overactive in the fatty (fa/fa) Zucker rat. The fa mutation affects the extracellular domain of the leptin receptor, but its impact on leptin action and neuropeptide Y neuronal activity is not fully known. We compared the effects of three doses of leptin given intracerebroventricularly and three doses of leptin injected intraperitoneally on food intake and hypothalamic neuropeptide Y mRNA, in lean and fatty Zucker rats. In lean rats, 4-h food intake was reduced in a dose-related fashion (P< 0.01) by all intracerebroventricular leptin doses and by intraperitoneal doses of 300 and 600 μg/kg. Neuropeptide Y mRNA levels were reduced by 28% and 21% after the highest intracerebroventricular and intraperitoneal doses respectively (P< 0.01 for both). In fatty rats, only the highest intracerebroventricular leptin dose reduced food intake (by 22%; P< 0.01). Neuropeptide Y mRNA levels were 100% higher in fatty rats than in lean animals, and were reduced by 18% (P< 0.01) after the highest intracerebroventricular leptin dose. Intraperitoneal injection had no effect on food intake and neuropeptide Y mRNA. The fa/fa Zucker rat is therefore less sensitive to leptin given intracerebroventricularly and particularly intraperitoneally, suggesting that the fa mutation interferes both with leptin's direct effects on neurons and its transport into the central nervous system. Obesity in the fa/fa Zucker rat may be partly due to the inability of leptin to inhibit hypothalamic neuropeptide Y neurons.

Postnatal intracerebroventricular exposure to leptin causes an altered adult female phenotype

2004 ◽  
Vol 287 (6) ◽  
pp. E1132-E1141 ◽  
Author(s):  
Amit Varma ◽  
Jing He ◽  
Bo-Chul Shin ◽  
Lisa A. Weissfeld ◽  
Sherin U. Devaskar
Keyword(s):  
Food Intake ◽  
Neuropeptide Y ◽  
Adult Female ◽  
Leptin Receptor ◽  
Postnatal Period ◽  
Female Progeny ◽  
Melanocyte Stimulating Hormone ◽  
Female Phenotype ◽  
Leptin Sensitivity ◽  
Stimulating Hormone

We investigated the effect of daily intracerebroventricular (ICV) leptin administration (neonatal age 2–7 days) on hypothalamic neuropeptides (neuropeptide Y, α-melanocyte-stimulating hormone) that regulate food intake, body weight (BW) gain, and the metabolic/hormonal profile in suckling (8 and 21 days) and adult rat (35, 60, 90, and 120 days). ICV leptin (0.16 μg·g BW−1·dose−1; n = 70) led to a postnatal decline in BW ( P = 0.0002) that persisted only in the adult females ( P = 0.002). The postnatal decline in BW due to leptin was associated with a decline in food intake ( P = 0.01) and hypothalamic leptin receptor ( P = 0.008) and neuropeptide Y ( P = 0.008) immunoreactivities and an increase in α-melanocyte-stimulating hormone ( P = 0.008) immunoreactivity. In addition, hyperinsulinemia ( P = 0.01) with hypocorticosteronemia ( P = 0.007) occurred during the postnatal period with hypercorticosteronemia ( P = 0.007) and hypoleptinemia ( P = 0.008) and an increase in leutinizing hormone ( P = 0.01) in the adult male and female progeny. Persistent hyperinsulinemia ( P = 0.015) with hyperglycemia ( P = 0.008) and glucose intolerance ( P = 0.001) were observed only in the adult female. We conclude that postnatal leptin administration alters the adult female phenotype and speculate that this may relate to retention of leptin sensitivity resulting in a lipoatrophic state.

scholarly journals Signal Transducer and Activator of Transcription-3 Is Required in Hypothalamic Agouti-Related Protein/Neuropeptide Y Neurons for Normal Energy Homeostasis

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3346-3354 ◽  
Author(s):  
Lijie Gong ◽  
Fayi Yao ◽  
Kristin Hockman ◽  
Henry H. Heng ◽  
Gregory J. Morton ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Metabolic Effects ◽  
Cytokine Signaling ◽  
Mrna Levels ◽  
Signal Transducer ◽  
Related Protein ◽  
Fat Cell ◽  
Agouti Related Protein

Signal transducer and activator of transcription (Stat)-3 signals mediate many of the metabolic effects of the fat cell-derived hormone, leptin. In mice, brain-specific depletion of either the long form of the leptin receptor (Lepr) or Stat3 results in comparable obese phenotypes as does replacement of Lepr with an altered leptin receptor locus that codes for a Lepr unable to interact with Stat3. Among the multiple brain regions containing leptin-sensitive Stat3 sites, cells expressing feeding-related neuropeptides in the arcuate nucleus of the hypothalamus have received much of the focus. To determine the contribution to energy homeostasis of Stat3 expressed in agouti-related protein (Agrp)/neuropeptide Y (Npy) arcuate neurons, Stat3 was deleted specifically from these cells, and several metabolic indices were measured. It was found that deletion of Stat3 from Agrp/Npy neurons resulted in modest weight gain that was accounted for by increased adiposity. Agrp/Stat3-deficient mice also showed hyperleptinemia, and high-fat diet-induced hyperinsulinemia. Stat3 deletion in Agrp/Npy neurons also resulted in altered hypothalamic gene expression indicated by increased Npy mRNA and decreased induction of suppressor of cytokine signaling-3 in response to leptin. Agrp mRNA levels in the fed or fasted state were unaffected. Behaviorally, mice without Stat3 in Agrp/Npy neurons were mildly hyperphagic and hyporesponsive to leptin. We conclude that Stat3 in Agrp/Npy neurons is required for normal energy homeostasis, but Stat3 signaling in other brain areas also contributes to the regulation of energy homeostasis.

Role of hypoleptinemia during cold adaptation in Brandt's voles (Lasiopodomys brandtii)

2009 ◽  
Vol 297 (5) ◽  
pp. R1293-R1301 ◽  
Author(s):  
Gang-Bin Tang ◽  
Jian-Guo Cui ◽  
De-Hua Wang
Keyword(s):  
Food Intake ◽  
Cold Adaptation ◽  
Leptin Receptor ◽  
Uncoupling Protein ◽  
Cytokine Signaling ◽  
Mrna Levels ◽  
Serum Leptin ◽  
Brown Adipose ◽  
Lasiopodomys Brandtii

Brandt's voles Lasiopodomys brandtii exhibit large increases in nonshivering thermogenesis to cope with chronic cold exposure, resulting in compensatory hyperphagia and fat mobilization. These physiological events are accompanied by a remarkable reduction in serum leptin levels. However, the role of hypoleptinemia in cold adaptation in this species is still unknown. In the present study, we tested the hypothesis that hypoleptinemia contributes to increases in food intake and brown adipose tissue (BAT) thermogenesis by modifying hypothalamic neuropeptides in cold-exposed Brandt's voles. Adult male voles were transferred to 5°C for 28 days. Accompanied by a decrease in serum leptin levels, hypothalamic agouti-related protein (AgRP) mRNA levels were significantly increased, but there were no changes in the long form of leptin receptor (Ob-Rb), suppressor of cytokine signaling 3 (SOCS3), neuropeptide Y (NPY) mRNA, proopiomelanocortin (POMC), and cocaine- and amphetamine-regulated peptide (CART) mRNA levels in the hypothalamus. When cold-exposed voles were returned to warm (23°C) for 28 days, body mass, food intake, serum leptin, and AgRP mRNA were restored to control levels. Leptin administration in cold-exposed voles decreased food intake as well as hypothalamic AgRP mRNA levels. There were no significant effects of leptin administration on hypothalamic Ob-Rb, SOCS3, NPY, POMC, CART mRNA, and uncoupling protein 1 levels under cold conditions. These results suggest that hypoleptinemia partially contributes to cold-induced hyperphagia, which might involve the elevation of hypothalamic AgRP gene expression.

scholarly journals 20 YEARS OF LEPTIN: Connecting leptin signaling to biological function

2014 ◽  
Vol 223 (1) ◽  
pp. T25-T35 ◽  
Author(s):  
Margaret B Allison ◽  
Martin G Myers
Keyword(s):  
Energy Balance ◽  
Signaling Pathways ◽  
Glucose Homeostasis ◽  
Molecular Mechanisms ◽  
Leptin Receptor ◽  
Protein Tyrosine Phosphatases ◽  
Cytokine Signaling ◽  
Cellular Mechanisms ◽  
Leptin Signaling

Hypothalamic leptin action promotes negative energy balance and modulates glucose homeostasis, as well as serving as a permissive signal to the neuroendocrine axes that control growth and reproduction. Since the initial discovery of leptin 20 years ago, we have learned a great deal about the molecular mechanisms of leptin action. An important aspect of this has been the dissection of the cellular mechanisms of leptin signaling, and how specific leptin signals influence physiology. Leptin acts via the long form of the leptin receptor LepRb. LepRb activation and subsequent tyrosine phosphorylation recruits and activates multiple signaling pathways, including STAT transcription factors, SHP2 and ERK signaling, the IRS-protein/PI3Kinase pathway, and SH2B1. Each of these pathways controls specific aspects of leptin action and physiology. Important inhibitory pathways mediated by suppressor of cytokine signaling proteins and protein tyrosine phosphatases also limit physiologic leptin action. This review summarizes the signaling pathways engaged by LepRb and their effects on energy balance, glucose homeostasis, and reproduction. Particular emphasis is given to the multiple mouse models that have been used to elucidate these functions in vivo.

scholarly journals High Intakes of [6S]-5-Methyltetrahydrofolic Acid Compared with Folic Acid during Pregnancy Programs Central and Peripheral Mechanisms Favouring Increased Food Intake and Body Weight of Mature Female Offspring

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1477
Author(s):  
Emanuela Pannia ◽  
Rola Hammoud ◽  
Ruslan Kubant ◽  
Jong Yup Sa ◽  
Rebecca Simonian ◽  
...  
Keyword(s):  
Body Weight ◽  
Folic Acid ◽  
Food Intake ◽  
Leptin Receptor ◽  
Liver Weight ◽  
Female Offspring ◽  
Mature Female ◽  
Cytokine Signaling ◽  
Light Cycle ◽  
Energy Regulation

Supplementation with [6S]-5-methyltetrahydrofolic acid (MTHF) is recommended as an alternative to folic acid (FA) in prenatal supplements. This study compared equimolar gestational FA and MTHF diets on energy regulation of female offspring. Wistar rats were fed an AIN-93G diet with recommended (2 mg/kg diet) or 5-fold (5X) intakes of MTHF or FA. At weaning, female offspring were fed a 45% fat diet until 19 weeks. The 5X-MTHF offspring had higher body weight (>15%), food intake (8%), light-cycle energy expenditure, and lower activity compared to 5X-FA offspring (p < 0.05). Both the 5X offspring had higher plasma levels of the anorectic hormone leptin at birth (60%) and at 19 weeks (40%), and lower liver weight and total liver lipids compared to the 1X offspring (p < 0.05). Hypothalamic mRNA expression of leptin receptor (ObRb) was lower, and of suppressor of cytokine signaling-3 (Socs3) was higher in the 5X-MTHF offspring (p < 0.05), suggesting central leptin dysregulation. In contrast, the 5X-FA offspring had higher expression of genes encoding for dopamine and GABA- neurotransmitter receptors (p < 0.01), consistent with their phenotype and reduced food intake. When fed folate diets at the requirement level, no differences were found due to form in the offspring. We conclude that MTHF compared to FA consumed at high levels in the gestational diets program central and peripheral mechanisms to favour increased weight gain in the offspring. These pre-clinical findings caution against high gestational intakes of folates of either form and encourage clinical trials examining their long-term health effects when consumed during pregnancy.

In vivo action of a new octadecaneuropeptide antagonist on neuropeptide Y and corticotropin-releasing hormone mRNA levels in rat

2005 ◽  
Vol 141 (2) ◽  
pp. 156-160 ◽  
Author(s):  
V. Compère ◽  
S. Li ◽  
J. Leprince ◽  
M.C. Tonon ◽  
H. Vaudry ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
Mrna Levels ◽  
Corticotropin Releasing Hormone ◽  
Releasing Hormone
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