scholarly journals Identification of a discrete neuronal circuit that relays insulin signaling into the brain to regulate glucose homeostasis

2021 ◽  
Author(s):  
Mouna El Mehdi ◽  
Saloua Takhlidjt ◽  
Mélodie Devère ◽  
Arnaud Arabo ◽  
Marie-Anne Le Solliec ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Inhibitory Effect ◽  
Neuronal Population ◽  
Biologically Active ◽  
Hypothalamic Nucleus ◽  
Hypothalamic Area ◽  
Antihyperglycemic Effect ◽  
Hypothalamic Regulation

26RFa (QRFP) is a biologically active peptide that regulates glucose homeostasis by acting as an incretin and by increasing insulin sensitivity at the periphery. 26RFa is also produced by a neuronal population localized in the hypothalamus. In the present study, we have investigated whether the 26RFa neurons may be involved in the hypothalamic regulation of glucose homeostasis. Our data indicate that 26RFa, i.c.v. injected, induces a robust antihyperglycemic effect associated with an increase of insulin production by the pancreatic islets. In addition, we found that insulin strongly stimulates 26RFa expression and secretion by the hypothalamus. RNAscope experiments revealed that neurons expressing 26RFa in the lateral hypothalamic area and the ventromedial hypothalamic nucleus also express the insulin receptor and that insulin induces the expression of 26RFa in these neurons. Concurrently, we show that the central antihyperglycemic effect of insulin is abolished in presence of a 26RFa receptor (GPR103) antagonist as well as in mice deficient for 26RFa. Finally, our data indicate that the hypothalamic 26RFa neurons are not involved in the central inhibitory effect of insulin on hepatic glucose production, but mediate the central effects of the hormone on its own peripheral production. To conclude, in the present study we have identified a novel actor of the hypothalamic regulation of glucose homeostasis, the 26RFa/GPR103 system and we provide the evidence that this neuronal peptidergic system is a key relay for the central regulation of glucose metabolism by insulin.

scholarly journals Leptin Action in the Ventromedial Hypothalamic Nucleus Is Sufficient, But Not Necessary, to Normalize Diabetic Hyperglycemia

Endocrinology ◽  
2013 ◽  
Vol 154 (9) ◽  
pp. 3067-3076 ◽  
Author(s):  
Thomas H. Meek ◽  
Miles E. Matsen ◽  
Mauricio D. Dorfman ◽  
Stephan J. Guyenet ◽  
Vincent Damian ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Leptin Receptor ◽  
Brain Area ◽  
Receptor Gene ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Hypothalamic Nucleus ◽  
Leptin Signaling ◽  
Brown Adipose ◽  
Tracer Dilution

In rodent models of type 1 diabetes, leptin administration into brain ventricles normalizes blood glucose at doses that have no effect when given peripherally. The ventromedial nucleus of the hypothalamus (VMN) is a potential target for leptin's antidiabetic effects because leptin-sensitive neurons in this brain area are implicated in glucose homeostasis. To test this hypothesis, we injected leptin directly into the bilateral VMN of rats with streptozotocin-induced uncontrolled diabetes mellitus. This intervention completely normalized both hyperglycemia and the elevated rates of hepatic glucose production and plasma glucagon levels but had no effect on tissue glucose uptake in the skeletal muscle or brown adipose tissue as measured using tracer dilution techniques during a basal clamp. To determine whether VMN leptin signaling is required for leptin-mediated normalization of diabetic hyperglycemia, we studied mice in which the leptin receptor gene was deleted in VMN steroidogenic factor 1 neurons using cre-loxP technology. Our findings indicate leptin action within these neurons is not required for the correction of diabetic hyperglycemia by central leptin infusion. We conclude that leptin signaling in the VMN is sufficient to mediate leptin's antidiabetic action but may not be necessary for this effect. Leptin action within a distributed neuronal network may mediate its effects on glucose homeostasis.

scholarly journals Knockdown of Neuropeptide Y in the Dorsomedial Hypothalamus Promotes Hepatic Insulin Sensitivity in Male Rats

Endocrinology ◽  
2016 ◽  
Vol 157 (12) ◽  
pp. 4842-4852 ◽  
Author(s):  
Lin Li ◽  
C. Barbier de La Serre ◽  
Ni Zhang ◽  
Liang Yang ◽  
Hong Li ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Neuropeptide Y ◽  
Glucose Homeostasis ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Motor Nucleus ◽  
Hepatic Insulin Sensitivity ◽  
Hepatic Glucose

Recent evidence has shown that alterations in dorsomedial hypothalamic (DMH) neuropeptide Y (NPY) signaling influence glucose homeostasis, but the mechanism through which DMH NPY acts to affect glucose homeostasis remains unclear. Here we report that DMH NPY descending signals to the dorsal motor nucleus of the vagus (DMV) modulate hepatic insulin sensitivity to control hepatic glucose production in rats. Using the hyperinsulinemic-euglycemic clamp, we revealed that knockdown of NPY in the DMH by adeno-associated virus-mediated NPY-specific RNAi promoted insulin’s action on suppression of hepatic glucose production. This knockdown silenced DMH NPY descending signals to the DMV, leading to an elevation of hepatic vagal innervation. Hepatic vagotomy abolished the inhibitory effect of DMH NPY knockdown on hepatic glucose production, but this glycemic effect was not affected by vagal deafferentation. Together, these results demonstrate a distinct role for DMH NPY in the regulation of glucose homeostasis through the hepatic vagal efferents and insulin action on hepatic glucose production.

scholarly journals Glucose homeostasis is impaired in mice deficient in the neuropeptide 26RFa (QRFP)

2020 ◽  
Vol 8 (1) ◽  
pp. e000942
Author(s):  
Mouna El-Mehdi ◽  
Saloua Takhlidjt ◽  
Fayrouz Khiar ◽  
Gaëtan Prévost ◽  
Jean-Luc do Rego ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Pancreatic Islets ◽  
Glucose Homeostasis ◽  
Gene Knockout ◽  
Hepatic Glucose Production ◽  
Biologically Active ◽  
Mutant Mice ◽  
Insulin Production ◽  
Coding Region ◽  
The Impact

Introduction26RFa (pyroglutamyl RFamide peptide (QRFP)) is a biologically active peptide that has been found to control feeding behavior by stimulating food intake, and to regulate glucose homeostasis by acting as an incretin. The aim of the present study was thus to investigate the impact of 26RFa gene knockout on the regulation of energy and glucose metabolism.Research design and methods26RFa mutant mice were generated by homologous recombination, in which the entire coding region of prepro26RFa was replaced by the iCre sequence. Energy and glucose metabolism was evaluated through measurement of complementary parameters. Morphological and physiological alterations of the pancreatic islets were also investigated.ResultsOur data do not reveal significant alteration of energy metabolism in the 26RFa-deficient mice except the occurrence of an increased basal metabolic rate. By contrast, 26RFa mutant mice exhibited an altered glycemic phenotype with an increased hyperglycemia after a glucose challenge associated with an impaired insulin production, and an elevated hepatic glucose production. Two-dimensional and three-dimensional immunohistochemical experiments indicate that the insulin content of pancreatic β cells is much lower in the 26RFa−/− mice as compared with the wild-type littermates.ConclusionDisruption of the 26RFa gene induces substantial alteration in the regulation of glucose homeostasis, with in particular a deficit in insulin production by the pancreatic islets. These findings further support the notion that 26RFa is an important regulator of glucose homeostasis.

scholarly journals P0950EFFECT OF THYROID HORMONE TREATMENT ON RENAL REABSORPTION OF GLUCOSE IN ALLOXAN-INDUCED DIABETIC RATS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Gireesh Dayma
Keyword(s):  
Blood Glucose ◽  
Thyroid Hormone ◽  
Glucose Homeostasis ◽  
Hepatic Glucose Production ◽  
Liver Perfusion ◽  
Glucose Production ◽  
Diabetic Rats ◽  
Hepatic Glucose ◽  
Glucose Output ◽  
Renal Expression

Abstract Background and Aims The thyroid hormone (TH) plays an important role in glucose metabolism. Recently, we showed that the TH improves glycemia control by decreasing cytokines expression in the adipose tissue and skeletal muscle of alloxan-induced diabetic rats, which were also shown to present primary hypothyroidism. In this context, this study aims to investigate whether the chronic treatment of diabetic rats with T3 could affect other tissues that are involved in the control of glucose homeostasis, as the liver and kidney. Method Adult male Wistar rats were divided into nondiabetic, diabetic, and diabetic treated with T3 (1.5 ?g/100 g BW for 4 weeks). Diabetes was induced by alloxan monohydrate (150 mg/kg, BW, i.p.). Animals showing fasting blood glucose levels greater than 250 mg/dL were selected for the study. Results After treatment, we measured the blood glucose, serum T3, T4, TSH, and insulin concentration, hepatic glucose production by liver perfusion, liver PEPCK, GAPDH, and pAKT expression, as well as urine glucose concentration and renal expression of SGLT2 and GLUT2. T3 reduced blood glucose, hepatic glucose production, liver PEPCK, GAPDH, and pAKT content and the renal expression of SGLT2 and increased glycosuria. Conclusion Results suggest that the decreased hepatic glucose output and increased glucose excretion induced by T3 treatment are important mechanisms that contribute to reduce serum concentration of glucose, accounting for the improvement of glucose homeostasis control in diabetic rats.

scholarly journals Glucagon Deficiency Reduces Hepatic Glucose Production and Improves Glucose Tolerance In Adult Mice

2010 ◽  
Vol 31 (4) ◽  
pp. 606-606
Author(s):  
Aidan S. Hancock ◽  
Aiping Du ◽  
Jingxuan Liu ◽  
Mayumi Miller ◽  
Catherine L. May
Keyword(s):  
Glucose Homeostasis ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Postprandial Glucose ◽  
Glucagon Receptor ◽  
Glucose Levels ◽  
Adult Mice ◽  
Hepatic Glucose ◽  
Knockout Animals

Abstract The major role of glucagon is to promote hepatic gluconeogenesis and glycogenolysis to raise blood glucose levels during hypoglycemic conditions. Several animal models have been established to examine the in vivo function of glucagon in the liver through attenuation of glucagon via glucagon receptor knockout animals and pharmacological interventions. To investigate the consequences of glucagon loss to hepatic glucose production and glucose homeostasis, we derived mice with a pancreas specific ablation of the α-cell transcription factor, Arx, resulting in a complete loss of the glucagon-producing pancreatic α-cell. Using this model, we found that glucagon is not required for the general health of mice but is essential for total hepatic glucose production. Our data clarifies the importance of glucagon during the regulation of fasting and postprandial glucose homeostasis.

scholarly journals Prevention of Diabetes in db/db Mice by Dietary Soy Is Independent of Isoflavone Levels

Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5200-5211 ◽  
Author(s):  
Céline Zimmermann ◽  
Christopher R. Cederroth ◽  
Lucie Bourgoin ◽  
Michelangelo Foti ◽  
Serge Nef
Keyword(s):  
Glucose Homeostasis ◽  
Cell Function ◽  
Hepatic Glucose Production ◽  
Cell Mass ◽  
Glucose Production ◽  
Metabolic Effects ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Glucose Levels ◽  
Hepatic Glucose

Abstract Recent evidence points towards the beneficial use of soy proteins and isoflavones to improve glucose control and slow the progression of type 2 diabetes. Here, we used diabetic db/db mice fed a high soy-containing diet (SD) or a casein soy-free diet to investigate the metabolic effects of soy and isoflavones consumption on glucose homeostasis, hepatic glucose production, and pancreatic islet function. Male db/db mice fed with a SD exhibited a robust reduction in hyperglycemia (50%), correlating with a reduction in hepatic glucose production and preserved pancreatic β-cell function. The rapid decrease in fasting glucose levels resulted from an inhibition of gluconeogenesis and an increase in glycolysis in the liver of db/db mice. Soy consumption also prevented the loss of pancreatic β-cell mass and thus improved glucose-stimulated insulin secretion (3-fold), which partly accounted for the overall improvements in glucose homeostasis. Comparison of SD effects on hyperglycemia with differing levels of isoflavones or with purified isoflavones indicate that the beneficial physiological effects of soy are not related to differences in their isoflavone content. Overall, these findings suggest that consumption of soy is beneficial for improving glucose homeostasis and delaying the progression of diabetes in the db/db mice but act independently of isoflavone concentration.

302: Gestational low protein programming inhibits the suppression of hepatic glucose production and causes impaired glucose homeostasis

2016 ◽  
Vol 214 (1) ◽  
pp. S173
Author(s):  
Chellakkan Selvanesan Blesson ◽  
Amy Schutt ◽  
Shaji Chacko ◽  
Juan Marini ◽  
Meena Balakrishnan ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Low Protein ◽  
Hepatic Glucose

scholarly journals POMC neurons expressing leptin receptors coordinate metabolic responses to fasting via suppression of leptin levels

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Alexandre Caron ◽  
Heather M Dungan Lemko ◽  
Carlos M Castorena ◽  
Teppei Fujikawa ◽  
Syann Lee ◽  
...  
Keyword(s):  
Energy Balance ◽  
Glucose Homeostasis ◽  
Adrenergic Receptor ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Genetic Manipulations ◽  
Leptin Receptors ◽  
Hepatic Glucose ◽  
Sympathetic Nervous

Leptin is critical for energy balance, glucose homeostasis, and for metabolic and neuroendocrine adaptations to starvation. A prevalent model predicts that leptin’s actions are mediated through pro-opiomelanocortin (POMC) neurons that express leptin receptors (LEPRs). However, previous studies have used prenatal genetic manipulations, which may be subject to developmental compensation. Here, we tested the direct contribution of POMC neurons expressing LEPRs in regulating energy balance, glucose homeostasis and leptin secretion during fasting using a spatiotemporally controlled Lepr expression mouse model. We report a dissociation between leptin’s effects on glucose homeostasis versus energy balance in POMC neurons. We show that these neurons are dispensable for regulating food intake, but are required for coordinating hepatic glucose production and for the fasting-induced fall in leptin levels, independent of changes in fat mass. We also identify a role for sympathetic nervous system regulation of the inhibitory adrenergic receptor (ADRA2A) in regulating leptin production. Collectively, our findings highlight a previously unrecognized role of POMC neurons in regulating leptin levels.

Insulin action on the liver in vivo

2007 ◽  
Vol 35 (5) ◽  
pp. 1171-1174 ◽  
Author(s):  
A.D. Cherrington ◽  
M.C. Moore ◽  
D.K. Sindelar ◽  
D.S. Edgerton
Keyword(s):  
Insulin Action ◽  
Direct Action ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Inhibitory Effect ◽  
Fat Cell ◽  
Insulin Levels ◽  
Hepatic Glucose ◽  
Potent Inhibitory Effect

Insulin has a potent inhibitory effect on hepatic glucose production by direct action at hepatic receptors. The hormone also inhibits glucose production by suppressing both lipolysis in the fat cell and secretion of glucagon by the α-cell. Neural sensing of insulin levels appears to participate in control of hepatic glucose production in rodents, but a role for brain insulin sensing has not been documented in dogs or humans. The primary effect of insulin on the liver is its direct action.

scholarly journals O-GlcNAcylated p53 in the liver modulates hepatic glucose production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria J. Gonzalez-Rellan ◽  
Marcos F. Fondevila ◽  
Uxia Fernandez ◽  
Amaia Rodríguez ◽  
Marta Varela-Rey ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Transcriptional Activation ◽  
Cellular Response ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Diabetic Patients ◽  
Type 2 Diabetic Patients ◽  
Protein Levels ◽  
Hepatic Glucose

Abstractp53 regulates several signaling pathways to maintain the metabolic homeostasis of cells and modulates the cellular response to stress. Deficiency or excess of nutrients causes cellular metabolic stress, and we hypothesized that p53 could be linked to glucose maintenance. We show here that upon starvation hepatic p53 is stabilized by O-GlcNAcylation and plays an essential role in the physiological regulation of glucose homeostasis. More specifically, p53 binds to PCK1 promoter and regulates its transcriptional activation, thereby controlling hepatic glucose production. Mice lacking p53 in the liver show a reduced gluconeogenic response during calorie restriction. Glucagon, adrenaline and glucocorticoids augment protein levels of p53, and administration of these hormones to p53 deficient human hepatocytes and to liver-specific p53 deficient mice fails to increase glucose levels. Moreover, insulin decreases p53 levels, and over-expression of p53 impairs insulin sensitivity. Finally, protein levels of p53, as well as genes responsible of O-GlcNAcylation are elevated in the liver of type 2 diabetic patients and positively correlate with glucose and HOMA-IR. Overall these results indicate that the O-GlcNAcylation of p53 plays an unsuspected key role regulating in vivo glucose homeostasis.

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