scholarly journals Glucagon-Like Peptide-1 Decreases Intracerebral Glucose Content by Activating Hexokinase and Changing Glucose Clearance during Hyperglycemia

2012 ◽  
Vol 32 (12) ◽  
pp. 2146-2152 ◽  
Author(s):  
Michael Gejl ◽  
Lærke Egefjord ◽  
Susanne Lerche ◽  
Kim Vang ◽  
Bo Martin Bibby ◽  
...  
Keyword(s):  
Glucose Content ◽  
Brain Glucose ◽  
Glucose Levels ◽  
Hyperglycemic Clamp ◽  
Positron Emission ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Double Blinded ◽  
The Brain

Type 2 diabetes and hyperglycemia with the resulting increase of glucose concentrations in the brain impair the outcome of ischemic stroke, and may increase the risk of developing Alzheimer's disease (AD). Reports indicate that glucagon-like peptide-1 (GLP-1) may be neuroprotective in models of AD and stroke: Although the mechanism is unclear, glucose homeostasis appears to be important. We conducted a randomized, double-blinded, placebo-controlled crossover study in nine healthy males. Positron emission tomography was used to determine the effect of GLP-1 on cerebral glucose transport and metabolism during a hyperglycemic clamp with 18fluoro-deoxy-glucose as tracer. Glucagon-like peptide-1 lowered brain glucose ( P = 0.023) in all regions. The cerebral metabolic rate for glucose was increased everywhere ( P = 0.039) but not to the same extent in all regions ( P = 0.022). The unidirectional glucose transfer across the blood-brain barrier remained unchanged ( P = 0.099) in all regions, while the unidirectional clearance and the phosphorylation rate increased ( P = 0.013 and 0.017), leading to increased net clearance of the glucose tracer ( P = 0.006). We show that GLP-1 plays a role in a regulatory mechanism involved in the actions of GLUT1 and glucose metabolism: GLP-1 ensures less fluctuation of brain glucose levels in response to alterations in plasma glucose, which may prove to be neuroprotective during hyperglycemia.

scholarly journals Receptor occupancy of dual glucagon-like peptide 1/glucagon receptor agonist SAR425899 in individuals with type 2 diabetes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Olof Eriksson ◽  
Torsten Haack ◽  
Youssef Hijazi ◽  
Lenore Teichert ◽  
Veronique Tavernier ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Receptor Occupancy ◽  
Strong Interactions ◽  
Glucagon Receptor ◽  
Glucose Levels ◽  
Positron Emission ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Abstract Unimolecular dual agonists for the glucagon-like peptide 1 receptor (GLP1R) and glucagon receptor (GCGR) are emerging as a potential new class of important therapeutics in type 2 diabetes (T2D). Reliable and quantitative assessments of in vivo occupancy on each receptor would improve the understanding of the efficacy of this class of drugs. In this study we investigated the target occupancy of the dual agonist SAR425899 at the GLP1R in pancreas and GCGR in liver by Positron Emission Tomography/Computed Tomography (PET/CT). Patients with T2D were examined by [68Ga]Ga-DO3A-Tuna-2 and [68Ga]Ga-DO3A-Exendin4 by PET, to assess the GCGR in liver and GLP1R in pancreas, respectively. Follow up PET examinations were performed after 17 (GCGR) and 20 (GLP-1R) days of treatment with SAR425899, to assess the occupancy at each receptor. Six out of 13 included patients prematurely discontinued the study due to adverse events. SAR425899 at a dose of 0.2 mg daily demonstrated an average GCGR occupancy of 11.2 ± 14.4% (SD) in N = 5 patients and a GLP1R occupancy of 49.9 ± 13.3%. Fasting Plasma Glucose levels (− 3.30 ± 1.14 mmol/L) and body weight (− 3.87 ± 0.87%) were lowered under treatment with SAR425899. In conclusion, SAR425899 demonstrated strong interactions at the GLP1R, but no clear occupancy at the GCGR. The study demonstrates that quantitative target engagement of dual agonists can be assessed by PET.

scholarly journals PET evaluation of light-induced modulation of microglial activation and GLP-1R expression in depressive rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu Liu ◽  
Lizhen Wang ◽  
Donghui Pan ◽  
Mingzhu Li ◽  
Yaoqi Li ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Light Therapy ◽  
Emission Tomography ◽  
Noninvasive Evaluation ◽  
Mild Stress ◽  
Positron Emission ◽  
Therapeutic Choice ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
The Brain

AbstractLight therapy has been accepted as a promising therapeutic choice for depression. Positron emission tomography (PET) combined with specific radiotracers has great benefits for revealing pathogenesis and developing therapeutics. This study aimed to investigate the influences of light therapy on microglial activation and glucagon-like peptide-1 receptor (GLP-1R) expression in the brain of depressive rats using [18F]DPA-714 and [18F]exendin-4 PET. The results showed that chronic unpredictable mild stress (CUMS)-induced depressive rats had poorer performance in behavioral tests compared to normal rats (p < 0.05) and the depressive-like behavior could be ameliorated by light therapy. Besides, depressive rats had significantly higher [18F]DPA-714 uptake and lower [18F]FDG uptake compare to normal rats in 11 and 9 regions of interest (ROIs) of the brain, respectively (p < 0.05). After 5 weeks of light therapy, higher [18F]FDG and [18F]exendin-4 uptake was observed in most ROIs of light therapy-treated depressive rats compared to untreated depressive rats (p < 0.05) and no significant differences existed in [18F]DPA-714 uptake between the two groups. This study demonstrated that light therapy can ameliorate depressive-like behavior, improve glucose metabolism, and halt the decline of brain GLP-1R expression of depressive rats, but have no effects on microglial activation caused by CUMS. Besides, this study validated that [18F]DPA-714 and [18F]exendin-4 PET have the potential for noninvasive evaluation of microglial activation and GLP-1R expression in the brain of depression.

Pharmacophore modeling and molecular docking studies of acridines as potential DPP-IV inhibitors

2015 ◽  
Vol 93 (7) ◽  
pp. 721-729
Author(s):  
R. Abu Khalaf ◽  
Z. Jarekji ◽  
T. Al-Qirim ◽  
D. Sabbah ◽  
G. Shattat
Keyword(s):  
Type 2 Diabetes ◽  
Gastric Inhibitory Polypeptide ◽  
Pharmacophore Modeling ◽  
Docking Studies ◽  
Glucose Levels ◽  
Dpp Iv ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Circulating Levels

Inhibition of dipeptidyl peptidase-IV (DPP-IV) prevents the inactivation of gastric inhibitory polypeptide (GIP) and glucagon-like peptide–1 (GLP-1). This increases circulating levels of active GLP-1 and GIP and stimulates insulin secretion, which results in lowering of glucose levels and improvement of the glycemic control in patients with type 2 diabetes. In this study, pharmacophore modeling and docking experiments were carried out and a series of eight novel 2-ethoxy-6,9-disubstituted acridines (13, 15, and 17a–17f) have been designed and synthesized. Then, these compounds were evaluated for their ability to inhibit DPP-IV. Most of the synthesized compounds were proven to have anti-DPP-IV activity where compound 17b displayed the best activity of 43.8% inhibition at 30 μmol/L concentration. Results of this work might be helpful for further optimization to develop more potent DPP-IV inhibitors.

scholarly journals Brain Glucose Levels in Portacaval-Shunted Rats with Chronic, Moderate Hyperammonemia: Implications for Determination of Local Cerebral Glucose Utilization

1994 ◽  
Vol 14 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Nancy F. Cruz ◽  
Gerald A. Dienel
Keyword(s):  
Glucose Utilization ◽  
Normal Values ◽  
Brain Structures ◽  
Glucose Content ◽  
Brain Glucose ◽  
Glucose Levels ◽  
Lumped Constant ◽  
Dg Method ◽  
The Brain

Rates of glucose utilization (lCMRglc) in many structures of the brain of fed, portacaval-shunted rats, when assayed with the [14C]deoxyglucose (DG) method in our laboratory, were previously found to be unchanged (30 of 36 structures) or depressed (6 structures) during the first 4 weeks after shunting, but to rise progressively to higher than normal values in 25 of 36 structures from 4–12 weeks. In contrast, lCMRglc, when assayed with the [14C]glucose method in another laboratory, was depressed in most structures of brains of 4–8-week shunted rats that had relatively high brain ammonia levels. There was a possibility that the increases in lCMRglc obtained with the [14C]DG method may have been artifactual, due, in part, to a change in brain glucose content which could alter the value of the lumped constant of the DG method. Brain glucose levels of shunted rats were, therefore, assayed by both direct chemical measurement in freeze-blown samples and by determination of steady-state brain:plasma distribution ratios for [14C]methylglucose; the methylglucose distribution ratio varies as a function of plasma and tissue glucose contents. Within a week after shunting, ammonia levels in blood and brain rose to 0.25–0.30 m M and 0.35–0.70 μmol/g, respectively, and mean plasma glucose levels fell from 9–10 m M to 7.4–8.5 m M, and then remained nearly constant. Brains of fedshunted rats had normal glycogen levels and stable but moderately reduced glucose contents between 1 and 12 weeks (i.e., 1.9–2.2 μmol/g). [14C]Methylglucose distribution ratios were essentially the same as those in controls in 22 brain structures at 2 and 8 weeks after shunting. Because brain glucose levels remained stable from 1 to 12 weeks after shunting, there is no evidence to support the hypothesis that the value of the lumped constant would have changed and caused an artifactual rise in lCMRglc.

scholarly journals Brain Imaging of the GLP-1 Receptor in Obesity Using 68Ga-NODAGA-Exendin-4 PET

2021 ◽  
Vol 11 (12) ◽  
pp. 1647
Author(s):  
Laura N. Deden ◽  
Jan Booij ◽  
Joanes Grandjean ◽  
Judith R. Homberg ◽  
Eric J. Hazebroek ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Receptor Expression ◽  
Receptor Agonists ◽  
Glucose Levels ◽  
Pet Tracer ◽  
Positron Emission ◽  
Obese Subjects ◽  
Glucagon Like Peptide 1 ◽  
The Brain ◽  
Stimulation Of

Stimulation of glucagon-like peptide-1 (GLP-1) receptors increases the insulin release in the pancreas during high glucose levels, and also stimulates a feeling of satiety. Likewise, synthetic GLP-1 receptor agonists derived from exendin are used successfully in the treatment of type-2 diabetes mellitus and obesity. Interestingly, preclinical and clinical studies further suggest that GLP-1 receptor agonists may decrease motor, behavioral, and cognitive symptoms in (animal models) Parkinson’s disease and Alzheimer’s disease and may slow down neurodegeneration. These observations suggest stimulation of GLP-1 receptors in the brain. The GLP-1 positron emission tomography (PET) tracer 68Ga-NODAGA-exendin-4 has been developed and successfully used for imaging in humans. In an ongoing study on the effects of bariatric surgery on GLP-1 receptor expression, we performed 68Ga-NODAGA-exendin-4 PET in obese subjects. Here we evaluated whether GLP-1 receptor binding could be visualized in the central nervous system in 10 obese subjects (seven woman; body mass index: mean ± SD: 39 ± 4.4 kg/m2) before bariatric surgery. Although we observed clear uptake in the pituitary area (mean SUVmax 4.3 ± 2.3), we found no significant uptake in other parts of the brain. We conclude that 68Ga-NODAGA-exendin-4 PET cannot be used to analyze GLP-1 receptors in the brain of obese subjects.

scholarly journals Incretins today: multiple effects and therapeutic potential

2019 ◽  
Vol 22 (1) ◽  
pp. 70-78
Author(s):  
Oksana V. Tsygankova ◽  
Varvara V. Veretyuk ◽  
Alexander S. Ametov
Keyword(s):  
Therapeutic Potential ◽  
Incretin Hormones ◽  
Alcoholic Fatty Liver ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
The 1960S ◽  
Insulinotropic Peptide

Glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) are the incretin hormones initially discovered in the 1960s. GIP and GLP-1 have gained great scientific interest due to their properties in increasing insulin secretion and lowering blood glucose levels. The study of these incretin hormones has progressed substantially in recent decades, in that their systemic effects has begun to be actively discussed. In particular, incretins are involved in the pathogenesis of obesity and non-alcoholic fatty liver disease. Moreover, incretins are able to improve cognitive function, suppress the formation of -amyloid plaques and provide an oncoprotective effect. Recent data show promising oncoprotective effect of GLP-1 agonists on prostate and breast cancer. This review provides systematisation of recent data on the role and mechanisms of action of incretin hormones on carbohydrate metabolism, as well as effects not related to glucose homeostasis, which contributes to a better understanding of potential vectors for the development of incretinotropic therapy. In addition, this review offers insight into pathogenic prerequisites and highlights the current issues in creating innovative polyagonists for treatment of type 2 diabetes mellitus.

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