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Qi Y.,Elixir Pharmaceuticals Inc. | Longo K.A.,Elixir Pharmaceuticals Inc. | Giuliana D.J.,Elixir Pharmaceuticals Inc. | Gagne S.,Elixir Pharmaceuticals Inc. | And 9 more authors.
BMC Physiology | Year: 2011

Background: We and others have demonstrated previously that ghrelin receptor (GhrR) knock out (KO) mice fed a high fat diet (HFD) have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed GhrR KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in GhrR KO mice, we conducted both hyperglycemic (HG) and hyperinsulinemic-euglycemic (HI-E) clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity. Results: Consistent with glucose tolerance-test data, in HG clamp experiments, GhrR KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1st phase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, GhrR KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed GhrR KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd), and decreased hepatic glucose production (HGP). HFD-fed GhrR KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. GhrR KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in GhrR KO mice relative to WT mice. Conclusions: These results indicate that improved glucose homeostasis of GhrR KO mice is characterized by robust improvements of glucose disposal in both normal and metabolically challenged states, relative to WT controls. GhrR KO mice have an intact 1 st phase insulin response but require significantly less insulin for glucose disposal. Our experiments reveal that the insulin sensitivity of GhrR KO mice is due to both BW independent and dependent factors. We also provide several lines of evidence that a key feature of the GhrR KO mouse is maintenance of hepatic insulin sensitivity during metabolic challenge. © 2011 Qi et al; licensee BioMed Central Ltd.


Longo K.A.,Elixir Pharmaceuticals Inc. | Berryman D.E.,Ohio University | Kelder B.,Ohio University | Charoenthongtrakul S.,Elixir Pharmaceuticals Inc. | And 3 more authors.
Growth Hormone and IGF Research | Year: 2010

The goal of this study was to examine factors that contribute to energy balance in female GHR -/- mice. We measured energy intake, energy expenditure (EE), fuel utilization, body mass (Mb) changes and physical activity in 17 month-old female GHR -/- mice and their age-matched wild type littermates. The GHR -/- mice were smaller, consumed more food per unit Mb, had greater EE per unit Mb and had an increase in 24-h EE/Mb that was similar to the increase in their surface-area-to-volume ratio. Locomotor activity (LMA) was reduced in the GHR -/- mice, but the energetic cost associated with their LMA was greater than in wild type controls. Furthermore, Mb and LMA were independent explanatory covariates of most of the variance in EE, and when adjusted for Mb and LMA, the GHR -/- mice had higher EE during both the light and dark phases of the daily cycle. Respiratory quotient was lower in GHR -/- mice during the light phase, which indicated a greater utilization of lipid relative to carbohydrate in these mice. Additionally, GHR -/- mice had higher ratios of caloric intake to EE at several intervals during the dark phase, and this effect was greater and more sustained in the final 3 h of the dark phase. Therefore, we conclude that GHR -/- mice are able to overcome the substantial energetic challenges of dwarfism through several mechanisms that promote stable Mb. Relative to wild type mice, the GHR -/- mice consumed more calories per unit Mb, which offset the disproportionate increase in their daily energy expenditure. While GHR -/- mice oxidized a greater proportion of lipid during the light phase in order to meet their energy requirements, they achieved greater energy efficiency and storage during the dark phase through a combination of higher energy consumption and lower LMA. © 2009 Elsevier Ltd. All rights reserved.


Huber J.L.,Elixir Pharmaceuticals Inc | McBurney M.W.,Ottawa Health Research Institute | Distefano P.S.,Elixir Pharmaceuticals Inc | McDonagh T.,Elixir Pharmaceuticals Inc | McDonagh T.,Adnexus Therapeutics A BMS Company
Future Medicinal Chemistry | Year: 2010

Background: SRT1720 and SRT2183 were described recently as activators of the NAD+-dependent deacetylase, SIRT1. These molecules enhanced metabolic function when administered to rodents at doses of 100-500 mg/kg/day, purportedly by activating SIRT1 enzymatic activity in various tissues; however, considerable controversy surrounds these claims. Results: We find that these molecules do not activate SIRT1 deacetylase activity when tested in a variety of enzymatic assay formats and conditions. The compounds effectively decrease acetylated p53 in cells treated with DNA damaging agents but do so in cells that lack SIRT1, calling into question their designation as direct activators of SIRT1. In contrast, we find that the compounds inhibit p300 histone acetyltransferase activity in vitro, suggesting a possible mechanism for their effects in vivo. Conclusion: Structural features of these molecules may account for false-positive activation using fluorescence-based assays. © 2010 Future Science Ltd.


Longo K.A.,Elixir Pharmaceuticals Inc. | Charoenthongtrakul S.,Elixir Pharmaceuticals Inc. | Giuliana D.J.,Elixir Pharmaceuticals Inc. | Govek E.K.,Elixir Pharmaceuticals Inc. | And 3 more authors.
American Journal of Physiology - Regulatory Integrative and Comparative Physiology | Year: 2010

To define the relationship between the respiratory quotient (RQ) and energy intake (EI) and to determine the impact of spontaneous locomotor activity (LMA) in the development of diet-induced obesity (DIO), we fed C57BL/6 mice a high-fat diet (HFD) for either 4 days or 17 wk and analyzed them using indirect calorimetry. Importantly, changes in body mass during calorimetry (ΔM b) significantly covaried with RQ and EI; adjusting the data for ΔMb permitted an analysis of the energy-balanced state. The 24-h RQ strongly predicted 24-h EI, and the slope of this relationship was diet dependent (HFD or chow) but independent of the HFD feeding period. Early-stage DIO was characterized by dark-period hyperphagia and fat storage, offset by greater light-period lipid oxidation; later stage DIO mice had a milder hyperphagia and lower substrate flexibility. Consequently, whereas 24-h RQ equaled the food quotient of the HFD in both early- and late-stage DIO, the range of RQ values was negatively correlated with, and mostly explained by, 24-h EI only in late-stage DIO. Lean and early-stage DIO mice had similar LMA values that were reduced in late-stage DIO. However, LMA significantly explained variance in total energy expenditure (EE) in only early-stage DIO mice. This indicated that the link between LMA and EE was a transient adaptive response to early DIO, whereas the later loss of LMA did not explain body weight gain in C57BL/6 DIO mice. Copyright © 2010 American Physiological Society.


Longo K.A.,Elixir Pharmaceuticals Inc. | Govek E.K.,Elixir Pharmaceuticals Inc. | Nolan A.,Elixir Pharmaceuticals Inc. | McDonagh T.,Elixir Pharmaceuticals Inc. | And 12 more authors.
Journal of Pharmacology and Experimental Therapeutics | Year: 2011

Ghrelin influences a variety of metabolic functions through a direct action at its receptor, the GhrR (GhrR-1a). Ghrelin knockout (KO) and GhrR KO mice are resistant to the negative effects of high-fat diet (HFD) feeding. We have generated several classes of small-molecule GhrR antagonists and evaluated whether pharmacologic blockade of ghrelin signaling can recapitulate the phenotype of ghrelin/GhrR KO mice. Antagonist treatment blocked ghrelin-induced and spontaneous food intake; however, the effects on spontaneous feeding were absent in GhrR KO mice, suggesting target-specific effects of the antagonists. Oral administration of antagonists to HFD-fed mice improved insulin sensitivity in both glucose tolerance and glycemic clamp tests. The insulin sensitivity observed was characterized by improved glucose disposal with dramatically decreased insulin secretion. It is noteworthy that these results mimic those obtained in similar tests of HFD-fed GhrR KO mice. HFD-fed mice treated for 56 days with antagonist experienced a transient decrease in food intake but a sustained body weight decrease resulting from decreased white adipose, but not lean tissue. They also had improved glucose disposal and a striking reduction in the amount of insulin needed to achieve this. These mice had reduced hepatic steatosis, improved liver function, and no evidence of systemic toxicity relative to controls. Furthermore, GhrR KO mice placed on low- or high-fat diets had lifespans similar to the wild type, emphasizing the long-term safety of ghrelin receptor blockade. We have therefore demonstrated that chronic pharmacologic blockade of the GhrR is an effective and safe strategy for treating metabolic syndrome. Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics.


Patent
Elixir Pharmaceuticals Inc. | Date: 2013-05-24

Compound of formula (I) and methods of treating disorders by administering a compound of formula (I) are described herein. Examples of disorders include neoplastic disorders, fat-cell related disorders, neurodegenerative disorders, and metabolic disorders.


Patent
Elixir Pharmaceuticals Inc. | Date: 2011-11-30

Disclosed are methods of treating a disorder of the stomach, intestine or duodenum in a human subject. The method includes administering to the subject, a pharmaceutical composition comprising a compound that increases gastrointestinal motility (e.g., by modulating myenteric nerve activity) and/or induces the secretion or production of growth hormone.


PubMed | Elixir Pharmaceuticals Inc.
Type: Journal Article | Journal: Future medicinal chemistry | Year: 2011

SRT1720 and SRT2183 were described recently as activators of the NAD+-dependent deacetylase, SIRT1. These molecules enhanced metabolic function when administered to rodents at doses of 100-500 mg/kg/day, purportedly by activating SIRT1 enzymatic activity in various tissues; however, considerable controversy surrounds these claims.We find that these molecules do not activate SIRT1 deacetylase activity when tested in a variety of enzymatic assay formats and conditions. The compounds effectively decrease acetylated p53 in cells treated with DNA damaging agents but do so in cells that lack SIRT1, calling into question their designation as direct activators of SIRT1. In contrast, we find that the compounds inhibit p300 histone acetyltransferase activity in vitro, suggesting a possible mechanism for their effects in vivo.Structural features of these molecules may account for false-positive activation using fluorescence-based assays.


Patent
Elixir Pharmaceuticals Inc. | Date: 2015-06-04

Compound of formula (I) and methods of treating disorders by administering a compound of formula (I) are described herein. Examples of disorders include neoplastic disorders, fat-cell related disorders, neurodegenerative disorders, and metabolic disorders.


PubMed | Elixir Pharmaceuticals Inc
Type: Journal Article | Journal: The Journal of pharmacology and experimental therapeutics | Year: 2011

Ghrelin influences a variety of metabolic functions through a direct action at its receptor, the GhrR (GhrR-1a). Ghrelin knockout (KO) and GhrR KO mice are resistant to the negative effects of high-fat diet (HFD) feeding. We have generated several classes of small-molecule GhrR antagonists and evaluated whether pharmacologic blockade of ghrelin signaling can recapitulate the phenotype of ghrelin/GhrR KO mice. Antagonist treatment blocked ghrelin-induced and spontaneous food intake; however, the effects on spontaneous feeding were absent in GhrR KO mice, suggesting target-specific effects of the antagonists. Oral administration of antagonists to HFD-fed mice improved insulin sensitivity in both glucose tolerance and glycemic clamp tests. The insulin sensitivity observed was characterized by improved glucose disposal with dramatically decreased insulin secretion. It is noteworthy that these results mimic those obtained in similar tests of HFD-fed GhrR KO mice. HFD-fed mice treated for 56 days with antagonist experienced a transient decrease in food intake but a sustained body weight decrease resulting from decreased white adipose, but not lean tissue. They also had improved glucose disposal and a striking reduction in the amount of insulin needed to achieve this. These mice had reduced hepatic steatosis, improved liver function, and no evidence of systemic toxicity relative to controls. Furthermore, GhrR KO mice placed on low- or high-fat diets had lifespans similar to the wild type, emphasizing the long-term safety of ghrelin receptor blockade. We have therefore demonstrated that chronic pharmacologic blockade of the GhrR is an effective and safe strategy for treating metabolic syndrome.

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