Abstract 606: Impaired Glucose Metabolism in the Triggering Receptor Expressed in Myeloid Cells Like Transcript- 1 Null Mice A Link to Obesity

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Elizabeth Castro Rivera ◽  
Abdías Díaz Rosado ◽  
Anthony V Washington
Keyword(s):  
Serum Insulin ◽  
Insulin Response ◽  
Myeloid Cells ◽  
Tolerance Test ◽  
Similar Response ◽  
Fatty Acid Production ◽  
Glucose Levels ◽  
Significant Difference

Fat rich foods have been shown to produce increased body weight and diabetes in various strains of mice. When fed ad libitum with a high fat diet (HFD), apolipoprotein E deficient ( apoe -/- ) mice develop hypercholesterolemia, but are not known to be obese. Our laboratory demonstrated that the triggering receptor expressed in myeloid cells (TREM) like transcript-1 (TLT-1), as a potential target for intervention during atherosclerosis, diabetes, and obesity. Crossing the treml1 -/- mouse onto an apoe -/- background (DKO), we found DKO mice had smaller lesions than apoe -/- mice, yet had significantly higher triglycerides and weight gain over a 20-week period of HFD. Further investigation demonstrated treml1 -/- mice to have higher cholesterol than wild type mice (wt), suggesting the treml1 mutation contributes to the phenotype observed in DKO mice. Glucose evaluation of treml1 -/- , treml1 +/- and wt mice, showed a significant difference in basal glucose, and in plasma glucose clearance, as revealed by intraperitoneal (IP) glucose tolerance test. Analysis of serum insulin by ELISA showed no differences, while IP insulin tolerance test revealed treml1 -/- and treml1 +/- mice present apparent insulin hypersensitivity, as represented by the steady glucose decline 15 min post injection, with no recovery after two hours. Western blot performed in various tissues, demonstrated the presence of a TLT-1 splice variant that lacks the extracellular domain (TLT-1s), in the adipose tissue of treml1 -/- but not wt mice. Analysis of insulin response, in vivo by insulin sensitivity assay and in vitro using TSA 201 cells transfected with TLT-1s to determine the effect on AKT activation, revealed enhanced phosphorylation in the presence of TLT-1, with a similar response observed in vitro. This data support a model where TLT-1s modulation of AKT phosphorylation, increases adipocyte glucose uptake, leading to: low blood glucose levels, increased fatty acid production and storage, and the obese phenotype we observed in our mice.

scholarly journals Maintaining a Physiological Blood Glucose Level with ‘Glucolevel’, a Combination of Four Anti-Diabetes Plants Used in the Traditional Arab Herbal Medicine

2008 ◽  
Vol 5 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Omar Said ◽  
Stephen Fulder ◽  
Khaled Khalil ◽  
Hassan Azaizeh ◽  
Eli Kassis ◽  
...  
Keyword(s):  
Juglans Regia ◽  
Human Fibroblasts ◽  
Tolerance Test ◽  
Positive Control ◽  
Diabetic Rats ◽  
Yeast Cells ◽  
Sugar Uptake ◽  
Glucose Levels

Safety and anti-diabetic effects of Glucolevel, a mixture of dry extract of leaves of theJuglans regiaL,Olea europeaL,Urtica dioicaL andAtriplex halimusL were evaluated usingin vivoandin vitrotest systems. No sign of toxic effects (using LDH assay) were seen in cultured human fibroblasts treated with increasing concentrations of Glucolevel. Similar observations were seenin vivostudies using rats (LD50: 25 g/kg). Anti-diabetic effects were evidenced by the augmentation of glucose uptake by yeast cells (2-folds higher) and by inhibition of glucose intestinal absorption (∼49%) in a rat gut-segment. Furthermore, treatment with Glucolevel of Streptozotocin-induced diabetic rats for 2–3 weeks showed a significant reduction in glucose levels [above 400 ± 50 mg/dl to 210 ± 22 mg/dl (P< 0.001)] and significantly improved sugar uptake during the glucose tolerance test, compared with positive control. In addition, glucose levels were tested in sixteen human volunteers, with the recent onset of type 2 diabetes mellitus, who received Glucolevel tablets 1 × 3 daily for a period of 4 weeks. Within the first week of Glucolevel consumption, baseline glucose levels were significantly reduced from 290 ± 40 to 210 ± 20 mg/dl. At baseline, a subgroup of eleven of these subjects had glucose levels below 300 mg% and the other subgroup had levels ≥ 300 mg%. Clinically acceptable glucose levels were achieved during the 2–3 weeks of therapy in the former subgroup and during the 4th week of therapy in the latter subgroup. No side effect was reported. In addition, a significant reduction in hemoglobin A1C values (8.2 ± 1.03 to 6.9 ± 0.94) was found in six patients treated with Glucolevel. Results demonstrate safety, tolerability and efficacy of herbal combinations of four plants that seem to act differently but synergistically to regulate glucose-homeostasis.

scholarly journals Loss-of-Function Mutation of the Galanin Gene Is Associated with Perturbed Islet Function in Mice

Endocrinology ◽  
2004 ◽  
Vol 145 (7) ◽  
pp. 3190-3196 ◽  
Author(s):  
Bo Ahrén ◽  
Giovanni Pacini ◽  
David Wynick ◽  
Nils Wierup ◽  
Frank Sundler
Keyword(s):  
Insulin Secretion ◽  
Islet Cells ◽  
Insulin Response ◽  
Tolerance Test ◽  
Glucose Disposal ◽  
Islet Function ◽  
Loss Of Function ◽  
Euglycemic Hyperinsulinemic Clamp

Abstract The neuropeptide galanin is expressed in sympathetic nerve terminals that surround islet cells and inhibits insulin secretion. To explore its role for islet function, we studied mice with a loss-of-function mutation in the galanin gene [galanin knockout (KO) mice]. Intravenous 2-deoxy-glucose, which activates both the sympathetic and parasympathetic branches of the autonomic nervous system, caused an initial (1–5 min) inhibition of insulin secretion that was impaired in galanin KO mice (P = 0.027), followed by a subsequent stimulation of insulin secretion that was augmented in galanin KO mice (P &lt; 0.01). Similar effects were seen after chemical sympathectomy by 6-hydroxydopamine. In contrast, galanin KO mice had a reduced insulin response to glucose, both in vivo (P &lt; 0.001) and in isolated islets (P &lt; 0.001), and to arginine, both in vivo (P = 0.012) and in vitro (P = 0.018). During an iv glucose tolerance test, galanin KO mice had impaired glucose disposal (P = 0.005) due to a reduced insulin response (P &lt; 0.001) and a reduced insulin-independent glucose elimination (glucose effectiveness; P = 0.040). Insulin sensitivity, as judged by a euglycemic, hyperinsulinemic clamp technique, was slightly increased in galanin KO mice (P = 0.032). We conclude that 1) galanin may contribute to sympathetic influences inhibiting insulin secretion in mice, and 2) galanin KO mice have a reduced glucose-induced insulin secretion.

Incretin release from gut is acutely enhanced by sugar but not by sweeteners in vivo

2009 ◽  
Vol 296 (3) ◽  
pp. E473-E479 ◽  
Author(s):  
Yukihiro Fujita ◽  
Rhonda D. Wideman ◽  
Madeleine Speck ◽  
Ali Asadi ◽  
David S. King ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Sweet Taste ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Glucose Levels ◽  
Zucker Diabetic Fatty Rats ◽  
Glucagon Like Peptide 1

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are released during meals from endocrine cells located in the gut mucosa and stimulate insulin secretion from pancreatic β-cells in a glucose-dependent manner. Although the gut epithelium senses luminal sugars, the mechanism of sugar sensing and its downstream events coupled to the release of the incretin hormones are not clearly elucidated. Recently, it was reported that sucralose, a sweetener that activates the sweet receptors of taste buds, triggers incretin release from a murine enteroendocrine cell line in vitro. We confirmed that immunoreactivity of α-gustducin, a key G-coupled protein involved in taste sensing, is sometimes colocalized with GIP in rat duodenum. We investigated whether secretion of incretins in response to carbohydrates is mediated via taste receptors by feeding rats the sweet-tasting compounds saccharin, acesulfame potassium, d-tryptophan, sucralose, or stevia. Oral gavage of these sweeteners did not reduce the blood glucose excursion to a subsequent intraperitoneal glucose tolerance test. Neither oral sucralose nor oral stevia reduced blood glucose levels in Zucker diabetic fatty rats. Finally, whereas oral glucose increased plasma GIP levels ∼4-fold and GLP-1 levels ∼2.5-fold postadministration, none of the sweeteners tested significantly increased levels of these incretins. Collectively, our findings do not support the concept that release of incretins from enteroendocrine cells is triggered by carbohydrates via a pathway identical to the sensation of “sweet taste” in the tongue.

scholarly journals CYP2J2 attenuates metabolic dysfunction in diabetic mice by reducing hepatic inflammation via the PPARγ

2015 ◽  
Vol 308 (4) ◽  
pp. E270-E282 ◽  
Author(s):  
Rui Li ◽  
Xizhen Xu ◽  
Chen Chen ◽  
Yan Wang ◽  
Artiom Gruzdev ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Biological Effects ◽  
Tolerance Test ◽  
Mapk Signaling ◽  
Metabolic Dysfunction ◽  
Glucose Levels ◽  
Hepatic Cells ◽  
Insulin Tolerance

Epoxyeicosatrienoic acids (EETs) and arachidonic acid-derived cytochrome P450 (CYP) epoxygenase metabolites have diverse biological effects, including anti-inflammatory properties in the vasculature. Increasing evidence suggests that inflammation in type 2 diabetes is a key component in the development of insulin resistance. In this study, we investigated whether CYP epoxygenase expression and exogenous EETs can attenuate insulin resistance in diabetic db/db mice and in cultured hepatic cells (HepG2). In vivo, CYP2J2 expression and the accompanying increase in EETs attenuated insulin resistance, as determined by plasma glucose levels, glucose tolerance test, insulin tolerance test, and hyperinsulinemic euglycemic clamp studies. CYP2J2 expression reduced the production of proinflammatory cytokines in liver, including CRP, IL-6, IL-1β, and TNFα, and decreased the infiltration of macrophages in liver. CYP2J2 expression also decreased activation of proinflammatory signaling cascades by decreasing NF-κB and MAPK activation in hepatocytes. Interestingly, CYP2J2 expression and exogenous EET treatment increased glucose uptake and activated the insulin-signaling cascade both in vivo and in vitro, suggesting that CYP2J2 metabolites play a role in glucose homeostasis. Furthermore, CYP2J2 expression upregulated PPARγ, which has been shown to induce adipogenesis, which attenuates dyslipidemias observed in diabetes. All of the findings suggest that CYP2J2 expression attenuates the diabetic phenotype and insulin resistance via inhibition of NF-κB and MAPK signaling pathways and activation of PPARγ.

scholarly journals In Vitro and In Vivo Effects of Norathyriol and Mangiferin on α-Glucosidase

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Zhi-Long Shi ◽  
Yi-Dan Liu ◽  
Yun-Yun Yuan ◽  
Da Song ◽  
Mei-Feng Qi ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Glucose Tolerance Test ◽  
Fasting Blood Glucose ◽  
Tolerance Test ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
In Vivo Effects ◽  
Antidiabetic Effects

Norathyriol is a metabolite of mangiferin. Mangiferin has been reported to inhibit α-glucosidase. To the best of our knowledge, no study has been conducted to determine or compare those two compounds on inhibiting α-glucosidase in vitro and in vivo by far. In this study, we determined the inhibitory activity of norathyriol and mangiferin on α-glucosidase in vitro and evaluated their antidiabetic effect in diabetic mice. The results showed that norathyriol inhibited α-glucosidase in a noncompetitive manner with an IC50 value of 3.12 μM, which is more potent than mangiferin (IC50 = 358.54 μM) and positive drug acarbose (IC50 = 479.2 μM) in the zymological experiment. Both of norathyriol and mangiferin caused significant (p<0.05) reduction in fasting blood glucose and the blood glucose levels at two hours after carbohydrate loading and it was interesting that mangiferin and norathyriol can make the decline of the blood glucose earlier than other groups ever including normal group in the starch tolerance test. However, norathyriol and mangiferin did not significantly influence carbohydrate absorption in the glucose tolerance test. Therefore, the antidiabetic effects of norathyriol and mangiferin might be associated with α-glucosidase, and norathyriol was more potent than mangiferin.

scholarly journals Synthesis and In Vitro AMPK Activation of Cycloalkyl/Alkarylbiguanides with Robust In Vivo Antihyperglycemic Action

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Erika Gutierrez-Lara ◽  
Carlos Martínez-Conde ◽  
Edgar Rosales-Ortega ◽  
Juan José Ramírez-Espinosa ◽  
Julio C. Rivera-Leyva ◽  
...  
Keyword(s):  
Binding Pocket ◽  
Tolerance Test ◽  
Regulatory Subunit ◽  
Oral Glucose ◽  
Alkyl Aryl ◽  
Design Synthesis ◽  
Glucose Levels ◽  
Amp Activated Protein Kinase

This work describes the design, synthesis in one step, and the in vitro, in vivo, and in silico antidiabetic evaluation of a series of ten alicyclic and aromatic (alkyl +aryl: alkaryl)biguanides, analogues of metformin and phenformin. The design was conceived using isosteric replacement, chain-ring transformation, and lower and higher homologation strategies. All compounds were obtained as crystals and their structure was confirmed on the basis of their spectral data (NMR and mass spectra), and their purity was ascertained by microanalysis. Compounds were in vitro evaluated as activators of AMP-Activated Protein Kinase (AMPK). The results indicated that compounds 4, 5, and 6 showed similar or even better effect compared to metformin. Docking analysis was performed with regulatory subunit γ of AMPK, showing several interactions with nucleotide binding pocket. The in vivo evaluation of compounds 4–6 at a single dose of 50 mg/kg was performed in a murine experimental model of diabetes. The results showed an important and robust decrease of plasmatic glucose levels (−40%). Compound 6 was selected for an oral glucose tolerance test, showing an antihyperglycemic effect similar to metformin. The in vivo results indicated that compounds 4–6 may be effective in treating experimental T2DM.

Insulin Secretion and Glucose Tolerance after Islet Transplantation in Rats with Noninsulin-Dependent Diabetes Induced by Neonatal Streptozotocin

1997 ◽  
Vol 6 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Maria-Angeles Tormo ◽  
Trinidad Leon-Quinto ◽  
Catherine Saulnier ◽  
Danielle Bailbe ◽  
Patricia Serradas ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Insulin Release ◽  
Insulin Response ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Β Cells ◽  
Basal Plasma

The present study was designed to identify in a model of noninsulin-dependent diabetes induced by neonatal streptozotocin (n0-STZ), the long-term consequences of an islet graft upon 1) glucose handling of the recipient and, 2) glucose response of the residual β cells in the recipient pancreas. We have examined, 4 and 8 wk after islet implantation under the kidney capsule of syngeneic diabetic n0-STZ rats, their tolerance to glucose administered in vivo, together with their insulin release in response to glucose in vivo (oral glucose tolerance test) as well as in vitro (perfused pancreas). The results in the islet-grafted n0-STZ rats, were compared to those obtained in nongrafted nondiabetic rats and nongrafted n0-STZ rats. Our study shows that transplanting a limited number (900) of adult islets under the kidney capsule reverses to normal, many parameters of the noninsulin-dependent diabetic state in the n0-STZ rat model: these include body weight, basal plasma glucose in both the nonfasted and postabsorptive states, and basal plasma insulin in the postabsorptive state. Furthermore, tolerance to oral glucose administration was greatly improved in the transplanted rats and it was correlated with restoration of a manifest glucose-induced insulin secretion in vivo as evaluated (ΔI) during an oral glucose tolerance test. Our data clearly show that the insulin response to glucose from the endogenous pancreas of n0-STZ diabetic rat was not really improved by long-term (8 wk) basal normoglycemia. More precisely, we were able to detect a slight but significant improvement of the early phase of insulin release in vitro in response to glucose; however, the overall insulin response remained 15 times lower than the normal one with no reapparance of the late phase of insulin release. After cessation of glucose stimulation in vivo, off-response of insulin, which is also a landmark of the impaired insulin release by the β cells of n0-STZ rats, was still detectable in the perfused pancreas of the transplanted n0-STZ rats. Finally, because the reactivity to glucose of the endogenous residual β cells was not regained, the insulin released in vivo during the oral glucose test in the graft-bearing n0-STZ rats can be attributed mainly to functioning of the grafted islets population. Copyright © 1997 Elsevier Science Inc.

Evidence for defective glucose sensing by islets of fa/fa obese Zucker rats

1993 ◽  
Vol 71 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Catherine B. Chan ◽  
Ruth M. MacPhail ◽  
Katherine Mitton
Keyword(s):  
Insulin Secretion ◽  
Insulin Response ◽  
Glucose Sensing ◽  
Zucker Rats ◽  
Rat Islets ◽  
Glucose Levels ◽  
Half Maximal Effective Concentration ◽  
Glucose Stimulated Insulin Secretion

The hypothesis that a defect in glucose sensing by islets of fa/fa Zucker rats contributes to hyperinsulinemia in these animals was tested. Islets from lean and fa/fa rats were isolated by collagenase digestion and step-density gradient purification and then cultured overnight in Dulbecco's modified Eagle's medium containing 12.5 mM glucose. Obese rat islets were more sensitive to hypoglycemic glucose levels with half-maximal effective concentration (EC50) of 5.6 mM compared with an EC50 of 8.2 mM for lean rat islets. In contrast, responsiveness of both phenotypes to α-ketoisocaproate and quinine was similar. Mannoheptulose did not inhibit insulin secretion from fa/fa islets, although inhibitors of later events in the stimulus–secretion coupling pathway were normally inhibited by iodoacetate and diazoxide. Finally, starvation in vivo and culture of islets in low glucose concentrations (5 mM) in vitro both decreased glucose-stimulated insulin secretion from lean but not fa/fa rat islets. We conclude that fa/fa rat islets have an exaggerated insulin response to hypoglycemic stimuli, possibly as a result of a defect in B-cell glucokinase function.Key words: insulin secretion, obesity, glucose metabolism, starvation.

scholarly journals In vivo and in vitro suppression by leptin of glucose-stimulated insulin hypersecretion in high glucose-fed rats

2000 ◽  
pp. 431-437 ◽  
Author(s):  
G Widdup ◽  
JM Bryson ◽  
D Pawlak ◽  
JL Phuyal ◽  
GS Denyer ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Basal Insulin ◽  
Insulin Response ◽  
Fold Increase ◽  
Tolerance Test ◽  
Glycaemic Index ◽  
Basal Insulin Secretion ◽  
Glucose Stimulated Insulin Secretion

OBJECTIVES: Chronic feeding to rats of high glycaemic index (GI) diets results in the hypersecretion of insulin in response to an i.v. glucose load. The first aim of this study was to see if this exaggerated insulin response was accompanied by a hypersensitivity to glucose stimulation in isolated islets in vitro. The second aim was to see if the adipocyte factor, leptin, was able to alter insulin secretion in this model both in vivo and in vitro. DESIGN AND METHODS: Rats were fed for 6 weeks either a high GI diet in which the carbohydrate component was mostly glucose (GLUC diet) or a low GI diet containing mostly amylose (AMOSE diet). Rats then underwent an i.v. glucose tolerance test (ivGTT) (1g/kg) with and without a prior infusion of leptin (133 microg/kg perh). Islets were then isolated from these rats and basal and glucose-stimulated insulin secretion (GSIS) measured in both the absence and presence (100ng/ml) of leptin. RESULTS AND CONCLUSIONS: Peak insulin response during the ivGTT was 3-fold greater in GLUC rats (P<0.001). Leptin had no effect on AMOSE rat insulin response but lowered the GLUC rat response to AMOSE rat levels. In vitro, basal insulin secretion was 4-fold greater in GLUC rats (P<0.05). At 20mmol/l glucose, there was no further increase in insulin secretion in GLUC rats but a 2-fold increase in AMOSE rats. Leptin had no effect on basal insulin secretion or GSIS in AMOSE rats but reduced basal insulin secretion and GSIS in GLUC rats. These results show insulin hypersecretion in high GI-fed rats may be reduced by leptin.

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