scholarly journals Peptide-based GIP receptor inhibition exhibits modest metabolic changes in mice when administered either alone or combined with GLP-1 agonism

2019 ◽  
Author(s):  
Jason A. West ◽  
Soumitra S. Ghosh ◽  
David G. Parkes ◽  
Anastasia Tsakmaki ◽  
Rikke V. Grønlund ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Glucose Tolerance ◽  
Mouse Model ◽  
Metabolic Effects ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Gip Receptor

ABSTRACTObjectiveCombinatorial gut hormone therapy is one of the more promising strategies for identifying improved treatments for metabolic disease. Many approaches combine the established benefits of glucagon-like peptide-1 (GLP-1) agonism with one or more additional molecules with the aim of improving metabolic outcomes. Recent attention has been drawn to the glucose-dependent insulinotropic polypeptide (GIP) system due to compelling pre-clinical evidence describing the metabolic benefits of antagonising the GIP receptor (GIPR). We rationalised that benefit might be accrued from combining GIPR antagonism with GLP-1 agonism. To this end we investigated the metabolic effects of co-administration of previously reported peptide-based GIPR antagonists with the GLP-1 agonist liraglutide.MethodsTwo GIPR peptide antagonists, GIPA-1 (mouse GIP(3-30)NH2) and GIPA-2 (NαAc-K10[γEγE-C16]-Arg18-hGIP(5–42)), were pharmacologically characterised in vitro in an assay measuring cAMP production in CHO-K1 cells overexpressing the mouse GIPR. These peptides were then characterised in vivo in lean mice for their effect on oral glucose tolerance, as well as their ability to antagonize exogenous GIP action. Finally, a mouse model of diet-induced obesity (DIO) was used to investigate the potential metabolic benefits of chronic dosing of peptide-based GIPR antagonists, alone or in combination with liraglutide.ResultsIn vitro, both GIPR peptides exhibited potent antagonistic properties, with GIPA-2 being the more potent of the two. Acute in vivo administration of GIPA-1 during an oral glucose tolerance test (OGTT) had negligible effects on glucose tolerance and circulated insulin in lean mice. In contrast, GIPA-2 impaired glucose tolerance and attenuated circulating insulin levels, with offsetting effects on glycemia noted with co-administration with exogenous mouse GIP, suggesting true antagonism via GIPA-2 at the GIP receptor. Chronic administration studies in a DIO mouse model showed expected effects of GLP-1 agonism (via liraglutide), lowering food intake, body weight, fasting blood glucose and plasma insulin concentrations while improving glucose sensitivity, whereas delivery of either GIPR antagonist alone had negligible effects on these parameters. Interestingly, chronic dual therapy with the GIPR antagonists and GLP-1 showed separation from single intervention arms though augmented insulin sensitizing effects (modestly lowering insulin and HOMA-IR) and lowering plasmas triglycerides and free-fatty acids, with more notable effects observed with GIPA-1 compared to GIPA-2.ConclusionWe conclude that, in contrast to the well-documented effects of GLP-1R agonism, systemic administration of peptide-based GIPR antagonists demonstrate minimal benefit on metabolic parameters in DIO mice, exhibiting no major effects on body weight, food intake and glycaemic parameters. However, the co-administration of both a GIPR antagonist together with a GLP1 agonist uncovers interesting synergistic and beneficial effects on measures of insulin sensitivity, circulating lipids and certain adipose stores that seem influenced by the degree or nature of GIP receptor antagonism.

scholarly journals Intact Leptin Receptor Signalling is not Required for the Sustained Weight Loss and Appetite Suppression Induced by Roux-en-Y Gastric Bypass Surgery

2021 ◽  
Author(s):  
Mohammed K. Hankir ◽  
Laura Rotzinger ◽  
Arno Nordbeck ◽  
Caroline Corteville ◽  
Annett Hoffmann ◽  
...  
Keyword(s):  
Weight Loss ◽  
Gastric Bypass ◽  
Body Weight ◽  
Food Intake ◽  
Glucose Tolerance ◽  
Leptin Receptor ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Sustained Weight Loss ◽  
Obese Rats

Leptin is the archetypal adipokine that promotes a negative whole-body energy balance largely through its action on brain leptin receptors. As such, the sustained weight loss and food intake suppression induced by Roux-en-Y gastric bypass (RYGB) surgery have been attributed to enhancement of endogenous leptin action. We formally revisited this idea in Zucker Fatty fa/fa rats, an established genetic model of leptin receptor deficiency, and carefully compared their body weight, food intake and oral glucose tolerance after RYGB with that of sham-operated fa/fa (obese) and sham-operated fa/+ (lean) rats. We found that RYGB rats sustainably lost body weight, which converged with that of lean rats and was 25.5 % lower than that of obese rats by the end of the 4 week study period. Correspondingly, daily food intake of RYGB rats was similar to that of lean rats from the second postoperative week, while it was always at least 33.9 % lower than that of obese rats. Further, oral glucose tolerance of RYGB rats was normalized at the forth postoperative week. These findings assert that leptin is not an essential mediator of the sustained weight loss and food intake suppression as well as the improved glycemic control induced by RYGB, and instead point to additional circulating and/or neural factors.

scholarly journals Oral Supplementation with Physiological Doses of Leptin During Lactation in Rats Improves Insulin Sensitivity and Affects Food Preferences Later in Life

Endocrinology ◽  
2007 ◽  
Vol 149 (2) ◽  
pp. 733-740 ◽  
Author(s):  
Juana Sánchez ◽  
Teresa Priego ◽  
Mariona Palou ◽  
Aixa Tobaruela ◽  
Andreu Palou ◽  
...  
Keyword(s):  
Body Weight ◽  
Insulin Sensitivity ◽  
Food Intake ◽  
Glucose Tolerance ◽  
Oral Glucose Tolerance Test ◽  
Glucose Tolerance Test ◽  
Food Preferences ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Oral Glucose Tolerance

We have previously described that neonate rats supplemented with physiological doses of oral leptin during lactation become more protected against overweight in adulthood. The purpose of this study was to characterize further the long-term effects on glucose and leptin homeostasis and on food preferences. Neonate rats were supplemented during lactation with a daily oral dose of leptin or the vehicle. We followed body weight and food intake of animals until the age of 15 months, and measured glucose, insulin, and leptin levels under different feeding conditions: ad libitum feeding, 14-h fasting, and 3-h refeeding after fasting. An oral glucose tolerance test and a leptin resistance test were performed. Food preferences were also measured. Leptin-treated animals were found to have lower body weight in adulthood and to eat fewer calories than their controls. Plasma insulin levels were lower in leptin-treated animals than in their controls under the different feeding conditions, as was the increase in insulin levels after food intake. The homeostatic model assessment for insulin resistance index was significantly lower in leptin-treated animals, and the oral glucose tolerance test also indicated higher insulin sensitivity in leptin-treated animals. In addition, these animals displayed lower plasma leptin levels under the different feeding conditions and were also more responsive to exogenous leptin administration. Leptin-treated animals also showed a lower preference for fat-rich food than their controls. These observations indicate that animals supplemented with physiological doses of oral leptin during lactation were more protected against obesity and metabolic features of the metabolic syndrome.

scholarly journals Antihyperglycemic Effect of Lavandula pedunculata: In Vivo, In Vitro and Ex Vivo Approaches

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2019
Author(s):  
Salima Boutahiri ◽  
Mohamed Bouhrim ◽  
Chayma Abidi ◽  
Hamza Mechchate ◽  
Ali S. Alqahtani ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Aqueous Extract ◽  
Digestive Enzymes ◽  
Ex Vivo ◽  
Glucose Absorption ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Antihyperglycemic Effect

Lavandula pedunculata (Mill.) Cav. (LP) is one of lavender species traditionally used in Morocco to prevent or cure diabetes, alone or in the form of polyherbal preparations (PHP). Therefore, the primary objective of this study was to test the antihyperglycemic effect of the aqueous extract of LP, alone and in combination with Punica granatum L. (PG) and Trigonella foenum-graecum L. (FGK). The secondary objective was to explore some mechanisms of action on the digestive functions. The antihyperglycemic effect of the aqueous extract of LP, alone and in combination with PG and FGK, was studied in vivo using an oral glucose tolerance test (OGTT). In addition, LP extract was tested on the activities of some digestive enzymes (pancreatic α-amylase and intestinal α-glucosidase) in vitro and on the intestinal absorption of glucose ex vivo using a short-circuit current (Isc) technique. Acute and chronic oral administration of LP aqueous extract reduced the peak of the glucose concentration (30 min, p < 0.01) and the area under the curve (AUC, p < 0.01). The effect of LP + PG was at the same amplitude to that of the positive control Metformin (MET). LP aqueous extract inhibited the pancreatic α-amylase with an IC50 almost identical to acarbose (0.44 ± 0.05 mg/mL and 0.36 ± 0.02 mg/mL, respectively), as well as the intestinal α-glucosidase, (IC50 = 131 ± 20 µg/mL) and the intestinal glucose absorption (IC50 = 81.28 ± 4.01 µg/mL) in concentration-dependent manners. LP aqueous extract exhibited potent actions on hyperglycemia, with an inhibition on digestive enzymes and glucose absorption. In addition, the combination with PG and FGK enhanced oral glucose tolerance in rats. These findings back up the traditional use of LP in type 2 diabetes treatment and the effectiveness of the alternative and combinative poly-phytotherapy (ACPP).

scholarly journals 4-Hydroxyisoleucine: experimental evidence of its insulinotropic and antidiabetic properties

1999 ◽  
Vol 277 (4) ◽  
pp. E617-E623 ◽  
Author(s):  
Christophe Broca ◽  
René Gross ◽  
Pierre Petit ◽  
Yves Sauvaire ◽  
Michèle Manteghetti ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Insulin Response ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Insulin Dependent ◽  
Glucose Tolerance Tests ◽  
Insulin Dependent Diabetic ◽  
Single Intravenous Administration

We have recently shown in vitro that 4-hydroxyisoleucine (4-OH-Ile), an amino acid extracted from fenugreek seeds, potentiates insulin secretion in a glucose-dependent manner. The present study was designed to investigate whether 4-OH-Ile could exert in vivo insulinotropic and antidiabetic properties. For this purpose, intravenous or oral glucose tolerance tests (IVGTTs and OGTTs, respectively) were performed not only in normal animals but also in a type II diabetes rat model. During IVGTT in normal rats or OGTT in normal dogs, 4-OH-Ile (18 mg/kg) improved glucose tolerance. The lactonic form of 4-OH-Ile was ineffective in normal rats. In non-insulin-dependent diabetic (NIDD) rats, a single intravenous administration of 4-OH-Ile (50 mg/kg) partially restored glucose-induced insulin response without affecting glucose tolerance; a 6-day subchronic administration of 4-OH-Ile (50 mg/kg, daily) reduced basal hyperglycemia, decreased basal insulinemia, and slightly, but significantly, improved glucose tolerance. In vitro, 4-OH-Ile (200 μM) potentiated glucose (16.7 mM)-induced insulin release from NIDD rat-isolated islets. So, the antidiabetic effects of 4-OH-Ile on NIDD rats result, at least in part, from a direct pancreatic B cell stimulation.

scholarly journals Chronic peptide-based GIP receptor inhibition exhibits modest glucose metabolic changes in mice when administered either alone or combined with GLP-1 agonism

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0249239
Author(s):  
Jason A. West ◽  
Anastasia Tsakmaki ◽  
Soumitra S. Ghosh ◽  
David G. Parkes ◽  
Rikke V. Grønlund ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Fasting Blood Glucose ◽  
Chronic Administration ◽  
Dual Therapy ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Beneficial Effects ◽  
Gut Hormone ◽  
Gip Receptor

Combinatorial gut hormone therapy is one of the more promising strategies for identifying improved treatments for metabolic disease. Many approaches combine the established benefits of glucagon-like peptide-1 (GLP-1) agonism with one or more additional molecules with the aim of improving metabolic outcomes. Recent attention has been drawn to the glucose-dependent insulinotropic polypeptide (GIP) system due to compelling pre-clinical evidence describing the metabolic benefits of antagonising the GIP receptor (GIPR). We rationalised that benefit might be accrued from combining GIPR antagonism with GLP-1 agonism. Two GIPR peptide antagonists, GIPA-1 (mouse GIP(3–30)NH2) and GIPA-2 (NαAc-K10[γEγE-C16]-Arg18-hGIP(5–42)), were pharmacologically characterised and both exhibited potent antagonist properties. Acute in vivo administration of GIPA-1 during an oral glucose tolerance test (OGTT) had negligible effects on glucose tolerance and insulin in lean mice. In contrast, GIPA-2 impaired glucose tolerance and attenuated circulating insulin levels. A mouse model of diet-induced obesity (DIO) was used to investigate the potential metabolic benefits of chronic dosing of each antagonist, alone or in combination with liraglutide. Chronic administration studies showed expected effects of liraglutide, lowering food intake, body weight, fasting blood glucose and plasma insulin concentrations while improving glucose sensitivity, whereas delivery of either GIPR antagonist alone had negligible effects on these parameters. Interestingly, chronic dual therapy augmented insulin sensitizing effects and lowered plasma triglycerides and free-fatty acids, with more notable effects observed with GIPA-1 compared to GIPA-2. Thus, the co-administration of both a GIPR antagonist with a GLP1 agonist uncovers interesting beneficial effects on measures of insulin sensitivity, circulating lipids and certain adipose stores that seem influenced by the degree or nature of GIP receptor antagonism.

The addition of cactus flour (Opuntia ficus indica) to the Western-style diet attenuates the onset of metabolic disorders in rats

2019 ◽  
Vol 49 (4) ◽  
pp. 564-579 ◽  
Author(s):  
Graziele Fonseca Cysneiros ◽  
Judith Libertad Chavez Gonzalez ◽  
Amanda Alves Marcelino da Silva ◽  
Taisy Cinthia Ferro Cavalcante ◽  
Omar Guzman Quevedo ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Glucose Tolerance ◽  
Dietary Intake ◽  
Relative Weight ◽  
Metabolic Parameters ◽  
Oral Glucose ◽  
Opuntia Ficus Indica ◽  
Content Type ◽  
Cholesterol Levels

PurposeThe purpose of this study is to investigate the effect of a 15-week dietary intake of cactus flour on metabolic parameters, body weight and dietary intake of rats.Design/methodology/approachMale Wistar rats were divided into four experimental groups (n= 8-10): control or westernized diets added or not of cactus flour. The following parameters were evaluated during the period of dietary manipulation: body weight, food intake, glycemic and lipid profile (oral glucose tolerance test, metabolic parameters, hepatic and muscular glycogen dosage), visceral and body fat (relative weight to body weight). Data were analyzed using Graphpad Prism®5,p= 0.05.FindingsAnimals fed on a Western-style diet together with flour cactus presented lower weight gain (335.7 ± 20.0,p= 0.05) over the evaluated period, even when the volume of food intake was not different among the groups. The addition of cactus flour to a Western-style diet appears to lower glucose levels at 30 and 60 min (p= 0.05), as shown in the glucose tolerance curve. There was a downward trend does fat stores, cholesterol levels and triglycerides. Therefore, it was concluded that this addition cactus flour is effective even when the diet is hyperlipidic, demonstrating its ability to attenuate risk parameters for the occurrence of metabolic syndromes such as sub fraction high cholesterol levels and glucose tolerance.Originality/valueThe addition of functional foods to diets may work to improve the harmful effects of this type of diet.Opuntia ficus indicahas high nutritional value and has hypoglycemic and hypolipemic properties besides being antioxidant.

Antidiabetic and in vitro antioxidant effects of hydromethanol extract of Paullinia pinnata root bark in alloxan-induced diabetic rat

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Onoja Samuel Okwudili ◽  
Nwachukwu Glory Chimaobi ◽  
Ezeja Maxwell Ikechukwu ◽  
Omeh Yusuf Ndukaku
Keyword(s):  
Glucose Tolerance ◽  
Antioxidant Activities ◽  
Post Treatment ◽  
Oral Glucose ◽  
Phytochemical Analysis ◽  
Root Bark ◽  
Distilled Water ◽  
Oral Glucose Tolerance ◽  
Reference Drug

Abstract Background The study evaluated phytochemical composition, antidiabetic, oral glucose tolerance test and in vitro antioxidant activities of hydromethanol extract of Paullinia pinnata root bark. Methods Cold maceration method was used in extract preparation and scavenging of 2,2-diphenyl-1-picrylhydrazyl radicals was used to evaluate antioxidant properties of the extract. Diabetes was induced with alloxan at the dose of 160 mg/kg. The antidiabetic activity of the extract was tested at doses of 50, 100 and 200 mg/kg, and glibenclamide was used as reference drug. Results Phytochemical analysis of the extract showed the presence of alkaloids, flavonoids, glycosides, tannins, saponins and terpenes/sterols. The extract produced a significant (p<0.05) time-dependent decrease in the fasting blood glucose (FBG) levels in the treated rats when compared with the distilled water treated rats, but did not produce dose-dependent effects. The extract 50, 100 and 200 mg/kg and glibenclamide (2 mg/kg) caused 83.62 %, 60.66 %, 47.77 % and 68.52 % reduction respectively in FBG at 6 h post-treatment while the distilled water (5 mL/kg) produced 8.12 % reduction in FBG at 6 h post treatment. The extract (50 mg/kg) and glibenclamide (2 mg/kg) produced a significant (p<0.05) oral glucose tolerance effect in both normoglycemic and diabetic rats. The extract produced concentration-dependent increase in antioxidant activity and had its optimum effect at 400 µg/mL concentration. Conclusions This study suggests that P. pinnata root bark has potent antidiabetic and antioxidant activities and also validates its use in folkloric medicine in the management of diabetes-related conditions.

scholarly journals In Vivo Activity of Posaconazole against Mucor spp. in an Immunosuppressed-Mouse Model

2002 ◽  
Vol 46 (7) ◽  
pp. 2310-2312 ◽  
Author(s):  
Qiu N. Sun ◽  
Laura K. Najvar ◽  
Rosie Bocanegra ◽  
David Loebenberg ◽  
John R. Graybill
Keyword(s):  
Body Weight ◽  
Mouse Model ◽  
Amphotericin B ◽  
Immunosuppressed Mouse ◽  
Tissue Burden

ABSTRACT The in vivo activities of posaconazole, itraconazole, and amphotericin B in neutropenic mice with zygomycosis were compared. The in vitro MICs of posaconazole and itraconazole for the strains of Mucor spp. used in this study ranged from 0.125 to 8 μg/ml and 0.25 to 8 μg/ml, respectively. The in vitro MIC range for amphotericin B is 0.125 to 0.25 μg/ml. At twice-daily doses of ≥15 mg/kg of body weight, posaconazole prolonged the survival of the mice and reduced tissue burden.

scholarly journals GIP receptor antagonist treatment causes weight loss in ovariectomized high fat diet-fed mice

2021 ◽  
Author(s):  
Geke Aline Boer ◽  
Jenna Hunt ◽  
Maria Gabe ◽  
Johanne Windeløv ◽  
Alexander Sparre-Ulricht ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
High Fat Diet ◽  
Body Weight Gain ◽  
Pharmacokinetic Profile ◽  
High Fat ◽  
Ovariectomized Mice ◽  
Gip Receptor

Background and purpose The incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), secreted by the enteroendocrine K-cells in the proximal intestine, may regulate lipid metabolism and adiposity but its exact role in these processes is unclear. Experimental approach We characterized in vitro and in vivo antagonistic properties of a novel GIP analogue, mGIPAnt-1. We further assessed the in vivo pharmacokinetic profile of this antagonist, as well as its ability to affect high-fat diet (HFD)-induced body weight gain in ovariectomized mice during an 8-week treatment period. Key results mGIPAnt-1 showed competitive antagonistic properties to the GIP receptor (GIPR) in vitro as it inhibited GIP-induced cAMP accumulation in COS-7 cells. Furthermore, mGIPAnt-1 was capable of inhibiting GIP-induced glucoregulatory and insulinotropic effects in vivo and has a favourable pharmacokinetic profile with a half-life of 7.2 hours in C57Bl6 female mice. Finally, sub-chronic treatment with mGIPAnt-1 in ovariectomized HFD mice resulted in a reduction of body weight and fat mass. Conclusion and Implications mGIPAnt-1 successfully inhibited acute GIP-induced effects in vitro and in vivo and sub-chronically induces resistance to HFD-induced weight gain in ovariectomized mice. Our results support the development of GIP antagonists for the therapy of obesity.

The Relation Between Glucose Tolerance and Insulin Binding to Circulating Monocytes in Obese Children

PEDIATRICS ◽  
1982 ◽  
Vol 70 (4) ◽  
pp. 633-637
Author(s):  
Kaichi Kida ◽  
Noriyoshi Watanabe ◽  
Yoshiki Fujisawa ◽  
Yoshinori Goto ◽  
Hiroshi Matsuda
Keyword(s):  
Glucose Tolerance ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Tolerance Test ◽  
Quantitative Relation ◽  
Immunoreactive Insulin ◽  
Oral Glucose ◽  
Obese Children

The quantitative relation between insulin binding to circulating monocytes in vitro and glucose tolerance in obese children in vivo is reported. Sixty-one obese children and 11 healthy control children participated in this study. The oral glucose tolerance test (OGTT) was performed by giving them glucose (1.75 gm/kg of body weight), orally in the morning, and the binding of 125I-labeled insulin to circulating monocytes in vitro was measured prior to OGTT. The glucose tolerance expressed by ΣBS (milligrams/100 ml), the sum of the plasma glucose (blood sugar [BS]) values at OGTT, was significantly correlated with the degree of overweight (r = .316, P &lt; .01) and more highly with ΣIRI (microunits per milliliter), the sum of immunoreactive insulin (IRI) values at OGTT (r = .512, P &lt; .001). Insulin binding to monocytes in vitro (picograms/106 cells) was inversely correlated with the degree of overweight (r = -. 687, P &lt; .001). Furthermore, ΣBS was inversely correlated significantly with insulin binding to monocytes in vitro (r = -.435, P &lt; .002). These data suggest that the decrease of insulin receptors might be one cause for the impairment of the glucose tolerance associated with obesity in children.

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