scholarly journals Loss of Agouti-Related Peptide Does Not Significantly Impact the Phenotype of Murine POMC Deficiency

Endocrinology ◽  
2011 ◽  
Vol 152 (5) ◽  
pp. 1819-1828 ◽  
Author(s):  
Marcus P. Corander ◽  
Debra Rimmington ◽  
Benjamin G. Challis ◽  
Stephen O'Rahilly ◽  
Anthony P. Coll
Keyword(s):  
Food Intake ◽  
Energy Homeostasis ◽  
Central Administration ◽  
Melanocortin System ◽  
Double Knockout ◽  
Related Peptide ◽  
Agonist Action ◽  
Physiological Relevance ◽  
Brown Adipose

The hypothalamic melanocortin system is unique among neuropeptide systems controlling energy homeostasis, in that both anorexigenic proopiomelanocortin (POMC)-derived and orexigenic Agouti related-peptide (AgRP)-derived ligands act at the same receptors, namely melanocortin 3 and 4 receptors (MC3/4R). AgRP clearly acts as a competitive antagonist at MC3R and MC4R but may also have an inverse agonist action at these receptors. The physiological relevance of this remains uncertain. We generated a mouse lacking both POMC and AgRP [double knockout (DKO) mouse]. Phenotyping was performed in the absence and presence of glucocorticoids, and the response to central peptide administration was studied. The phenotype of DKO mice is indistinguishable from that of mice lacking Pomc alone, with both exhibiting highly similar degrees of hyperphagia and increased body length, fat, and lean mass compared with wild-type controls. After a 24-h fast, there was no difference in the refeeding response between Pomc−/− and DKO mice. Similarly, corticosterone supplementation caused an equivalent increase in food intake and body weight in both genotypes. Although the central administration of [Nle4, d-Phe7]-α-MSH to DKO mice caused a decrease in food intake and an increase in brown adipose tissue Ucp1 expression, both of which could be antagonized with the coadministration of AgRP, there was no effect of AgRP alone. These data suggest AgRP acts predominantly as a melanocortin antagonist. If AgRP has significant melanocortin-independent actions, these are of insufficient magnitude in vivo to impact any of the detailed phenotypes we have measured under a wide variety of conditions.

scholarly journals Central administration of resistin promotes short-term satiety in rats

2005 ◽  
Vol 153 (3) ◽  
pp. R1-R5 ◽  
Author(s):  
Sulay Tovar ◽  
Rubén Nogueiras ◽  
Loraine Y C Tung ◽  
Tamara R Castañeda ◽  
María Jesús Vázquez ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Food Intake ◽  
Energy Homeostasis ◽  
Therapeutic Potential ◽  
Central Administration ◽  
Fos Protein ◽  
Physiological Relevance ◽  
Affect Body Weight ◽  
Hypothalamic Structure ◽  
Fasted Rats

Objective: Several hormones expressed in white adipose tissue influence food intake at the central level. We sought to determine whether resistin, a circulating adipose-derived hormone in rodents, has actions on the hypothalamus by determining the effects of central resistin injection on food intake and on hypothalamic Fos protein expression. Design: As resistin expression in adipose tissue is influenced by altered nutritional status, we studied the effect of central resistin in both fed and pre-fasted rats. Results: In fasted rats, central injection of resistin decreased food intake acutely and increased the number of cells that express Fos protein in the arcuate nucleus but not in any other hypothalamic structure. The effect on food intake was dose-dependent and did not result in the formation of a conditioned taste aversion. Conclusions: Taken together, these results provide the first evidence documenting a central action of resistin, which could be involved in a feedback loop targeting the hypothalamus. On the other hand, since we observed resistin mRNA in the arcuate and ventromedial nuclei of the hypothalamus, it is also possible that brain-derived resistin serves as a neuropeptide involved in the regulation of energy homeostasis. However, since resistin-induced satiety was modest and transient, as central administration for several days did not affect body weight, the physiological relevance and therapeutic potential of the observed principal phenomenon may be limited.

Repeated administration of the anorectic factor prolactin-releasing peptide leads to tolerance to its effects on energy homeostasis

2003 ◽  
Vol 285 (5) ◽  
pp. R1005-R1010 ◽  
Author(s):  
Kate L. J. Ellacott ◽  
Catherine B. Lawrence ◽  
Lynn E. Pritchard ◽  
Simon M. Luckman
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Energy Homeostasis ◽  
Body Weight Gain ◽  
Repeated Administration ◽  
Daily Injection ◽  
Central Administration ◽  
Brown Adipose ◽  
Prolactin Releasing Peptide

Central administration of a single dose of prolactin-releasing peptide (PrRP) causes a reduction in both fast-induced and nocturnal food intake and body weight gain. The aim of this study was to examine the effect of repeated administration of PrRP on energy homeostasis, including a measure of the expression of the mitochondrial uncoupling protein-1 (UCP-1) in brown adipose tissue. Conscious, free-feeding animals received central injections of PrRP (4 nmol icv) or vehicle. A single injection at 1000 caused a sustained hyperthermia over the 4-h test period and an increase in the expression of UCP-1 mRNA. Repeated, twice daily injection caused a reduction in body weight gain greater than that seen in pair-fed animals for the first 48-72 h. After 72 h, the animals became refractory to the actions of PrRP. The pair-fed group showed a reduction in UCP-1 mRNA expression at 48 h, which was reversed by PrRP treatment. This study indicates that PrRP exerts its effects on energy homeostasis in the short-medium term by reducing food intake and increasing energy expenditure.

scholarly journals The thermogenic effect of nesfatin-1 requires recruitment of the melanocortin system

2017 ◽  
Vol 235 (2) ◽  
pp. 111-122 ◽  
Author(s):  
Riccardo Dore ◽  
Luka Levata ◽  
Sogol Gachkar ◽  
Olaf Jöhren ◽  
Jens Mittag ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Heat Loss ◽  
Central Administration ◽  
Melanocortin System ◽  
Direct Calorimetry ◽  
Iodothyronine Deiodinase ◽  
Interscapular Brown Adipose Tissue ◽  
Peripheral Tissues ◽  
Dry Heat ◽  
Brown Adipose

Nesfatin-1 is a bioactive polypeptide expressed both in the brain and peripheral tissues and involved in the control of energy balance by reducing food intake. Central administration of nesfatin-1 significantly increases energy expenditure, as demonstrated by a higher dry heat loss; yet, the mechanisms underlying the thermogenic effect of central nesfatin-1 remain unknown. Therefore, in this study, we sought to investigate whether the increase in energy expenditure induced by nesfatin-1 is mediated by the central melanocortin pathway, which was previously reported to mediate central nesfatin-1´s effects on feeding and numerous other physiological functions. With the application of direct calorimetry, we found that intracerebroventricular nesfatin-1 (25 pmol) treatment increased dry heat loss and that this effect was fully blocked by simultaneous administration of an equimolar dose of the melanocortin 3/4 receptor antagonist, SHU9119. Interestingly, the nesfatin-1-induced increase in dry heat loss was positively correlated with body weight loss. In addition, as assessed with thermal imaging, intracerebroventricular nesfatin-1 (100 pmol) increased interscapular brown adipose tissue (iBAT) as well as tail temperature, suggesting increased heat production in the iBAT and heat dissipation over the tail surface. Finally, nesfatin-1 upregulated pro-opiomelanocortin and melanocortin 3 receptor mRNA expression in the hypothalamus, accompanied by a significant increase in iodothyronine deiodinase 2 and by a nonsignificant increase in uncoupling protein 1 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha mRNA in the iBAT. Overall, we clearly demonstrate that nesfatin-1 requires the activation of the central melanocortin system to increase iBAT thermogenesis and, in turn, overall energy expenditure.

scholarly journals Effects of Chronic Intracerebroventricular Infusion of RFamide-Related Peptide-3 on Energy Metabolism in Male Mice

2020 ◽  
Vol 21 (22) ◽  
pp. 8606
Author(s):  
Shogo Moriwaki ◽  
Yuki Narimatsu ◽  
Keisuke Fukumura ◽  
Eiko Iwakoshi-Ukena ◽  
Megumi Furumitsu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Metabolism ◽  
Food Intake ◽  
Energy Expenditure ◽  
Body Mass ◽  
The Other ◽  
Related Peptide ◽  
Intracerebroventricular Infusion ◽  
Brown Adipose ◽  
The Masses

RFamide-related peptide-3 (RFRP-3), the mammalian ortholog of avian gonadotropin-inhibitory hormone (GnIH), plays a crucial role in reproduction. In the present study, we explored the other functions of RFRP-3 by investigating the effects of chronic intracerebroventricular infusion of RFRP-3 (6 nmol/day) for 13 days on energy homeostasis in lean male C57BL/6J mice. The infusion of RFRP-3 increased cumulative food intake and body mass. In addition, the masses of brown adipose tissue (BAT) and the liver were increased by the administration of RFRP-3, although the mass of white adipose tissue was unchanged. On the other hand, RFRP-3 decreased O2 consumption, CO2 production, energy expenditure, and core body temperature during a short time period in the dark phase. These results suggest that the increase in food intake and the decrease in energy expenditure contributed to the gain of body mass, including the masses of BAT and the liver. The present study shows that RFRP-3 regulates not only reproductive function, but also energy metabolism, in mice.

scholarly journals Gqα/G11α deficiency in dorsomedial hypothalamus leads to obesity resulting from decreased energy expenditure and impaired sympathetic nerve activity

2020 ◽  
Author(s):  
Eric A. Wilson ◽  
Hui Sun ◽  
Zhenzhong Cui ◽  
Marshal T. Jahnke ◽  
Mritunjay Pandey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Food Intake ◽  
Energy Expenditure ◽  
Energy Homeostasis ◽  
Dorsomedial Hypothalamus ◽  
Ambient Temperatures ◽  
Brown Adipose ◽  
Inhibit Food Intake ◽  
Specific Deletion

The G protein subunits Gqα and G11α (Gq/11α) couple receptors to phospholipase C, leading to increased intracellular calcium. In this study we investigated the consequences of Gq/11α deficiency in the dorsomedial hypothalamus (DMH), a critical site for the control of energy homeostasis. Mice with DMH-specific deletion of Gq/11α (DMHGq/11KO) were generated by stereotaxic injection of AAV-Cre-GFP into the DMH of Gqαflox/flox:G11α-/- mice. Compared to control mice that received DMH injection of AAV-GFP, DMHGq/11KO mice developed obesity associated with reduced energy expenditure without significant changes in food intake or physical activity. DMHGq/11KO mice showed no defects in the ability of the melanocortin agonist melanotan II to acutely stimulate energy expenditure or to inhibit food intake. At room temperature (22oC) DMHGq/11KO mice showed reduced sympathetic nervous system activity in brown adipose tissue (BAT) and heart, accompanied with decreased basal BAT Ucp1 gene expression and lower heart rates. These mice were cold intolerant when acutely exposed to cold (6oC for 5 hours) and had decreased cold-stimulated BAT Ucp1 gene expression. DMHGq/11KO mice also failed to adapt to gradually declining ambient temperatures and to develop adipocyte browning in inguinal white adipose tissue although their BAT Ucp1 was proportionally stimulated. Consistent with impaired cold-induced thermogenesis, the onset of obesity in DMHGq/11KO mice was significantly delayed when housed under thermoneutral conditions (30ºC). Thus, our results show that Gqα and G11α in the DMH are required for the control of energy homeostasis by stimulating energy expenditure and thermoregulation.

scholarly journals Structure–Activity Relationships of the Tetrapeptide Ac-His-Arg-(pI)DPhe-Tic-NH2 at the Mouse Melanocortin Receptors: Modification at the (pI)DPhe Position Leads to mMC3R Versus mMC4R Selective Ligands

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1463
Author(s):  
Katherine N. Schlasner ◽  
Mark D. Ericson ◽  
Skye R. Doering ◽  
Katie T. Freeman ◽  
Mary Weinrich ◽  
...  
Keyword(s):  
Food Intake ◽  
Metabolic Disorders ◽  
Energy Homeostasis ◽  
Biological Pathways ◽  
Melanocortin Receptors ◽  
Lead Compounds ◽  
Structure Activity ◽  
Selective Ligands ◽  
Selective Agonists

The five melanocortin receptors (MC1R–MC5R) are involved in numerous biological pathways, including steroidogenesis, pigmentation, and food intake. In particular, MC3R and MC4R knockout mice suggest that the MC3R and MC4R regulate energy homeostasis in a non-redundant manner. While MC4R-selective agonists have been utilized as appetite modulating agents, the lack of MC3R-selective agonists has impeded progress in modulating this receptor in vivo. In this study, the (pI)DPhe position of the tetrapeptide Ac-His-Arg-(pI)DPhe-Tic-NH2 (an MC3R agonist/MC4R antagonist ligand) was investigated with a library of 12 compounds. The compounds in this library were found to have higher agonist efficacy and potency at the mouse (m) MC3R compared to the MC4R, indicating that the Arg-DPhe motif preferentially activates the mMC3R over the mMC4R. This observation may be used in the design of new MC3R-selective ligands, leading to novel probe and therapeutic lead compounds that will be useful for treating metabolic disorders.

scholarly journals The Antiobesity Effects of Centrally Administered Neuromedin U and Neuromedin S Are Mediated Predominantly by the Neuromedin U Receptor 2 (NMUR2)

Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3101-3109 ◽  
Author(s):  
Andrea Peier ◽  
Jennifer Kosinski ◽  
Kimberly Cox-York ◽  
Ying Qian ◽  
Kunal Desai ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Homeostasis ◽  
Central Administration ◽  
Diet Induced Obesity ◽  
Inhibit Food Intake ◽  
Selective Agonists ◽  
Treatment Of Obesity ◽  
The Brain ◽  
Deficient Mice

Neuromedin U (NMU) and neuromedin S (NMS) are structurally related neuropeptides that have been reported to modulate energy homeostasis. Pharmacological data have shown that NMU and NMS inhibit food intake when administered centrally and that NMU increases energy expenditure. Additionally, NMU-deficient mice develop obesity, whereas transgenic mice overexpressing NMU are lean and hypophagic. Two high-affinity NMU/NMS receptors, NMUR1 and NMUR2, have been identified. NMUR1 is predominantly expressed in the periphery, whereas NMUR2 is predominantly expressed in the brain, suggesting that the effects of centrally administered NMU and NMS are mediated by NMUR2. To evaluate the role of NMUR2 in the regulation of energy homeostasis, we characterized NMUR2-deficient (Nmur2−/−) mice. Nmur2−/− mice exhibited a modest resistance to diet-induced obesity that was at least in part due to reduced food intake. Acute central administration of NMU and NMS reduced food intake in wild-type but not in Nmur2−/− mice. The effects on activity and core temperature induced by centrally administered NMU were also absent in Nmur2−/− mice. Moreover, chronic central administration of NMU and NMS evoked significant reductions in body weight and sustained reductions in food intake in mice. In contrast, Nmur2−/− mice were largely resistant to these effects. Collectively, these data demonstrate that the anorectic and weight-reducing actions of centrally administered NMU and NMS are mediated predominantly by NMUR2, suggesting that NMUR2-selective agonists may be useful for the treatment of obesity.

scholarly journals PDK1-Foxo1 in Agouti-Related Peptide Neurons Regulates Energy Homeostasis by Modulating Food Intake and Energy Expenditure

PLoS ONE ◽  
2011 ◽  
Vol 6 (4) ◽  
pp. e18324 ◽  
Author(s):  
Yongheng Cao ◽  
Masanori Nakata ◽  
Shiki Okamoto ◽  
Eisuke Takano ◽  
Toshihiko Yada ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Energy Homeostasis ◽  
Related Peptide

scholarly journals Peripheral administration of the N-terminal pro-opiomelanocortin fragment 1–28 to Pomc−/− mice reduces food intake and weight but does not affect adrenal growth or corticosterone production

2006 ◽  
Vol 190 (2) ◽  
pp. 515-525 ◽  
Author(s):  
Anthony P Coll ◽  
Martin Fassnacht ◽  
Steffen Klammer ◽  
Stephanie Hahner ◽  
Dominik M Schulte ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Homeostasis ◽  
Reduce Food Intake ◽  
Appetite Control ◽  
Concurrent Administration ◽  
Physiological Level ◽  
Sham Treatment ◽  
Acth Treatment

Pro-opiomelanocortin (POMC) is a polypeptide precursor that undergoes extensive processing to yield a range of peptides with biologically diverse functions. POMC-derived ACTH is vital for normal adrenal function and the melanocortin α-MSH plays a key role in appetite control and energy homeostasis. However, the roles of peptide fragments derived from the highly conserved N-terminal region of POMC are less well characterized. We have used mice with a null mutation in the Pomc gene (Pomc−/−) to determine the in vivo effects of synthetic N-terminal 1–28 POMC, which has been shown previously to possess adrenal mitogenic activity. 1–28 POMC (20 μg) given s.c. for 10 days had no effect on the adrenal cortex of Pomc−/− mice, with resultant cortical morphology and plasma corticosterone levels being indistinguishable from sham treatment. Concurrent administration of 1–28 POMC and 1–24 ACTH (30 μg/day) resulted in changes identical to 1–24 ACTH treatment alone, which consisted of upregulation of steroidogenic enzymes, elevation of corticosterone levels, hypertrophy of the zona fasciculate, and regression of the X-zone. However, treatment of corticosterone-depleted Pomc−/− mice with 1–28 POMC reduced cumulative food intake and total body weight. These anorexigenic effects were ameliorated when the peptide was administered to Pomc−/− mice with circulating corticosterone restored either to a low physiological level by corticosterone-supplemented drinking water (CORT) or to a supraphysiological level by concurrent 1–24 ACTH administration. Further, i.c.v. administration of 1–28 POMC to CORT-treated Pomc−/− mice had no effect on food intake or body weight. In wild-type mice, the effects of 1–28 POMC upon food intake and body weight were identical to sham treatment, but 1–28 POMC was able to ameliorate the hyperphagia induced by concurrent 1–24 ACTH treatment. In a mouse model which lacks all endogenous POMC peptides, s.c. treatment with synthetic 1–28 POMC alone can reduce food intake and body weight, but has no impact upon adrenal growth or steroidogenesis.

Enhanced splenomegaly and severe liver inflammation in haptoglobin/hemopexin double-null mice after acute hemolysis

Blood ◽  
2002 ◽  
Vol 100 (12) ◽  
pp. 4201-4208 ◽  
Author(s):  
Emanuela Tolosano ◽  
Sharmila Fagoonee ◽  
Emilio Hirsch ◽  
Franklin G. Berger ◽  
Heinz Baumann ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Plasma Membranes ◽  
Antioxidant Action ◽  
Liver Inflammation ◽  
Intravascular Hemolysis ◽  
Double Knockout ◽  
Radical Production ◽  
Physiological Relevance ◽  
Protective Proteins

Intravascular hemolysis is associated with several pathologic conditions that include hemoglobinopathies, trauma, malaria, and bacterial infections. Among plasma-protective proteins against oxidative damage caused by red blood cell rupture, haptoglobin and hemopexin are thought to play a crucial role. Haptoglobin and hemopexin, by binding with high-affinity hemoglobin and heme, respectively, exert an antioxidant action by preventing heme-catalyzed free radical production. Moreover, these proteins prevent iron loss by inhibiting glomerular filtration of hemoglobin and heme diffusion through plasma membranes. Analysis of single-null mice demonstrated the antioxidant action of haptoglobin and hemopexin in vivo and suggests that the 2 proteins cooperate in the resolution of hemolytic stress. To evaluate the physiological relevance of the haptoglobin-hemopexin system and the principal targets of its action, we generated haptoglobin-hemopexin double-knockout mice and analyzed them under basal conditions and after acute hemolysis. Whereas haptoglobin-hemopexin double-null mice displayed no obvious alteration in phenotype under basal conditions, nonlethal hemolytic stress in these animals led to pronounced splenomegaly as well as liver inflammation and fibrosis. These data demonstrate that haptoglobin and hemopexin together are essential for protection from splenomegaly and liver fibrosis resulting from intravascular hemolysis.

Sign in / Sign up

Export Citation Format

Share Document