scholarly journals Novel Biological Action of the Dipeptidylpeptidase-IV Inhibitor, Sitagliptin, as a Glucagon-Like Peptide-1 Secretagogue

Endocrinology ◽  
2012 ◽  
Vol 153 (2) ◽  
pp. 564-573 ◽  
Author(s):  
Ganesh V. Sangle ◽  
Lina M. Lauffer ◽  
Anthony Grieco ◽  
Shivangi Trivedi ◽  
Roman Iakoubov ◽  
...  

Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted into the circulation by the intestinal L cell. The dipeptidylpeptidase-IV (DPP-IV) inhibitor, sitagliptin, prevents GLP-1 degradation and is used in the clinic to treat patients with type 2 diabetes mellitus, leading to improved glycated hemoglobin levels. When the effect of sitagliptin on GLP-1 levels was examined in neonatal streptozotocin rats, a model of type 2 diabetes mellitus, a 4.9 ± 0.9-fold increase in basal and 3.6 ± 0.4-fold increase in oral glucose-stimulated plasma levels of active GLP-1 was observed (P < 0.001), in association with a 1.5 ± 0.1-fold increase in the total number of intestinal L cells (P < 0.01). The direct effects of sitagliptin on GLP-1 secretion and L cell signaling were therefore examined in murine GLUTag (mGLUTag) and human hNCI-H716 intestinal L cells in vitro. Sitagliptin (0.1–2 μm) increased total GLP-1 secretion by mGLUTag and hNCI-H716 cells (P < 0.01–0.001). However, MK0626 (1–50 μm), a structurally unrelated inhibitor of DPP-IV, did not affect GLP-1 secretion in either model. Treatment of mGLUTag cells with the GLP-1 receptor agonist, exendin-4, did not modulate GLP-1 release, indicating the absence of feedback effects of GLP-1 on the L cell. Sitagliptin increased cAMP levels (P < 0.01) and ERK1/2 phosphorylation (P < 0.05) in both mGLUTag and hNCI-H716 cells but did not alter either intracellular calcium or phospho-Akt levels. Pretreatment of mGLUTag cells with protein kinase A (H89 and protein kinase inhibitor) or MAPK kinase-ERK1/2 (PD98059 and U0126) inhibitors prevented sitagliptin-induced GLP-1 secretion (P < 0.05–0.01). These studies demonstrate, for the first time, that sitagliptin exerts direct, DPP-IV-independent effects on intestinal L cells, activating cAMP and ERK1/2 signaling and stimulating total GLP-1 secretion.

Endocrinology ◽  
2011 ◽  
Vol 152 (12) ◽  
pp. 4610-4619 ◽  
Author(s):  
Andrew J. Mulherin ◽  
Amy H. Oh ◽  
Helena Kim ◽  
Anthony Grieco ◽  
Lina M. Lauffer ◽  
...  

Glucagon-like peptide-17-36NH2 (GLP-1) is secreted by the intestinal L cell in response to both nutrient and neural stimulation, resulting in enhanced glucose-dependent insulin secretion. GLP-1 is therefore an attractive therapeutic for the treatment of type 2 diabetes. The antidiabetic drug, metformin, is known to increase circulating GLP-1 levels, although its mechanism of action is unknown. Direct effects of metformin (5–2000 μm) or another AMP kinase activator, aminoimidazole carboxamide ribonucleotide (100–1000 μm) on GLP-1 secretion were assessed in murine human NCI-H716, and rat FRIC L cells. Neither agent stimulated GLP-1 secretion in any model, despite increasing AMP kinase phosphorylation (P < 0.05–0.01). Treatment of rats with metformin (300 mg/kg, per os) or aminoimidazole carboxamide ribonucleotide (250 mg/kg, sc) increased plasma total GLP-1 over 2 h, reaching 37 ± 9 and 29 ± 9 pg/ml (P < 0.001), respectively, compared with basal (7 ± 1 pg/ml). Plasma activity of the GLP-1-degrading enzyme, dipeptidylpeptidase-IV, was not affected by metformin treatment. Pretreatment with the nonspecific muscarinic antagonist, atropine (1 mg/kg, iv), decreased metformin-induced GLP-1 secretion by 55 ± 11% (P < 0.05). Pretreatment with the muscarinic (M) 3 receptor antagonist, 1-1-dimethyl-4-diphenylacetoxypiperidinium iodide (500 μg/kg, iv), also decreased the GLP-1 area under curve, by 48 ± 8% (P < 0.05), whereas the antagonists pirenzepine (M1) and gallamine (M2) had no effect. Furthermore, chronic bilateral subdiaphragmatic vagotomy decreased basal secretion compared with sham-operated animals (7 ± 1 vs. 13 ± 1 pg/ml, P < 0.001) but did not alter the GLP-1 response to metformin. In contrast, pretreatment with the gastrin-releasing peptide antagonist, RC-3095 (100 μg/kg, sc), reduced the GLP-1 response to metformin, by 55 ± 6% (P < 0.01) at 30 min. These studies elucidate the mechanism underlying metformin-induced GLP-1 secretion and highlight the benefits of using metformin with dipeptidylpeptidase-IV inhibitors in patients with type 2 diabetes.


2021 ◽  
Vol 11 (5) ◽  

Dipeptidyl peptidase IV is a key regulator of insulin- stimulating hormones, glucagon-like peptide and glucose dependent insulinotrophic polypeptide. Thus it is a promising target for treatment of type 2 Diabetes mellitus. Inhibition of plasma Dipeptidyl peptidase IV enzyme lead to enhanced endogenous glucagon like peptide-1, GIP activity which ultimately results in the potentiating of insulin secretion by pancreatic cell and subsequent lowering blood glucose level, HbA [1c], glucose secretion, liver glucose production. One of the principal goals of diabetes management is to attain haemoglobin HbA [1c] treatment goals and prevent the onset or decrease the rate of occurrence of Microvascular conditions.2, 6 numerous treatment options are available for management of Type 2 Diabetes mellitus, various class of DPP IV inhibitor being explored such as Sitagliptin and Vildagliptin successfully launched. Several other novel DPP IV inhibitors are in pipeline, Unless there are clear contraindications, metformin monotherapy is prescribed, and if HbA [1c] targets are not attained after 3 months, 1 of several classes of agents could be added, such as sulfonylurea’s, Thiazolidinediones, dipeptidyl peptidase-4 inhibitors, - glucagon like peptide-1 receptor agonists, or basal insulin.2,6 Despite the broad range of therapeutic options, the attainment of HbA [1c] goals among patients with diabetes remains challenging, with just slightly more than half (52%) of diabetes patients attaining the common HbA [1c] goal of < 7.0%. The present review summarizes latest preclinical and clinical trial data of different DPP IV inhibitors with a special emphasis on their DPP8/9 fold selectivity and therapeutic advantages over GLP-1 based approach. Keywords: Diabetes 2, Dipeptidyl Peptidase-4, glucose-dependent insulinot


2020 ◽  
Vol 98 (3) ◽  
pp. 210-217
Author(s):  
A. Yu. Babenko ◽  
Yu. A. Kononova ◽  
M. V. Martjanova ◽  
A. V. Simanenkova ◽  
M. A. Kokina ◽  
...  

Due to the high efficiency of glucagon-like peptide-1 (GLP-1) receptor agonists therapy in only a part of patients, the search for predictors of response to the treatment is a relevant problem. Purpose. The purpose is to compare the efficacy of liraglutide and exenatide therapy in obese patients with type 2 diabetes mellitus (T2DM) and to evaluate the predictors of response to glycated hemoglobin (HbA1c), weight and lipids reduction. Material and methods. The study included 47 patients with type 2 diabetes and obesity who received GLP-1 receptor agonists therapy. 26 patients were treated with liraglutide, 21 patients were treated with exenatide. We measured the parameters of carbohydrate and lipid metabolism, the levels of hormones involved in glucose and lipids metabolism and in appetite regulation. Blood pressure was measured. These parameters were evaluated at baseline and after 24 weeks of treatment. Results. Patients receiving exenatide therapy showed a tendency towards more frequent HbA1c level reduction by 1% or more (60% versus 30.4%, p = 0.07). The effects of liraglutide and exenatide on weight and waist circumference were comparable. When assessing the predictors of response to the therapy, a more pronounced decrease in HbA1c level (by 1% or more) was in the patients with a higher initial HbA1c level (8.7 (8.2; 9.7) versus 8.2 (6.9; 8.7)%, p = 0.04), as well as with a higher initial GLP-1 level (0.12 (0.05; 0.17) versus 0.040 (0.01; 0.09) ng/ml.) A more significant decrease in the triglycerides (TG) level was detected in patients with a higher level of glucose-dependent insulinotropic peptide (GIP) before therapy (409 (316.0; 431.4) pg/ml in patients who reduced TG level by 30% or more and 331.5 (324.9; 367.1) pg/ml in patients with a lower decrease in TG level). Among the studied parameters, no predictors of body mass reduction were revealed. Conclusion. Measurement of HbA1c, GLP-1, GIP level may be useful to predict the efficacy of GLP-1 receptor agonists therapy.


2018 ◽  
Vol 12 (4) ◽  
pp. 202-209 ◽  
Author(s):  
Spyridon N. Karras ◽  
Eleni Rapti ◽  
Theocharis Koufakis ◽  
Angeliki Kyriazou ◽  
Dimitrios G. Goulis ◽  
...  

2021 ◽  
Vol 37 (6) ◽  
pp. 74-83
Author(s):  
A.Yu. Gorbunova ◽  
E.P. Sannikova ◽  
I.I. Gubaidullin ◽  
O.M. Ignatova ◽  
M.Yu. Kopaeva ◽  
...  

In addition to the previously developed recombinant modified human glucagon-like peptide 1 (rmglp1, Glypin), a recombinant modified human glucose-dependent insulinotropic peptide (RMGIP) has been obtained. A new universal reverse-phase HPLC technique has been proposed allowing quantitative analysis of rmGlp1 and rmGip separately and as part of a two-component preparation. The data show that the design of recombinant human rmGip according to the Glypine formula makes it possible to produce one-component and two-component preparations containing various rmGip and rmGlp1 protein ratios ranging from 1:0 to 20:1, using cell biomass samples mixed in predetermined proportions. Studies of human rmGip activity in a mouse model revealed reduced specific activity and signs of weak antagonistic effects. In this regard, there is a need for further study of human rmGip activity in a mouse model, including the use of alternative mouse or rat rmGip. type 2 diabetes mellitus; two-component drug, glucose-dependent insulinotropic peptide, glucagon-like peptide-1 The work was supported by the Internal Grant from National Research Center Kurchatov Institute.


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