This study concerns whether the pancreatic beta cell expresses cell-surface ectopeptidases that are capable of proteolysis of peptide hormones and neuropeptides that modify glucose-dependent insulin release. These biochemical investigations of the RINm5F cell line found that these cells express ectopeptidases. We have characterized the limited endoproteolysis of GLP-1 (7-36) amide that occurs in the presence of RINm5F plasma membranes. The products and the sensitivity to specific peptidase inhibitors of the proteolysis is characteristic of neutral endopeptidase (NEP) 24.11. Vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP), amylin, glucagon, glucose-dependent insulinotropic polypeptide (GIP), and exendin-4 also undergo proteolysis in the presence of RIN cell membranes. NEP 24.11-activity in RIN cell membranes was confirmed using a specific fluorogenic assay, by histochemistry, and by comparison with the recombinant enzyme with respect to the kinetics of proteolysis of GLP-1 (7-36) amide and of a fluorogenic substrate. Specific fluorogenic assays revealed the presence of aminopeptidase N and the absence of aminopeptidase A and of dipeptidylpeptidase IV.
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Sci Transl Med
December 2024
Molecular Pharmacology, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indianapolis, IN 46285, USA.
Orally bioavailable, synthetic nonpeptide agonists (NPAs) of the glucagon-like peptide-1 receptor (GLP-1R) may offer an effective, scalable pharmacotherapy to address the metabolic disease epidemic. One of the first molecules in the emerging class of GLP-1R NPAs is orforglipron, which is in clinical development for treating type 2 diabetes and obesity. Here, we characterized the pharmacological properties of orforglipron in comparison with peptide-based GLP-1R agonists and other NPAs.
View Article and Find Full Text PDFJ Am Chem Soc
September 2024
Division of Chemistry and Chemical Engineering and Materials Process and Simulation Center, California Institute of Technology, Pasadena, California 91125, United States.
Recently, there has been a great deal of excitement about new glucagon-like peptide 1 receptor (GLP-1R) agonists (e.g., semaglutide and tirzepatide) that have received FDA approval for type 2 diabetes and obesity.
View Article and Find Full Text PDFWorld J Diabetes
August 2024
Department of Pathological Physiology, Shandong Second Medical University, Weifang 261053, Shandong Province, China.
Background: Impaired hypoglycaemic counterregulation has emerged as a critical concern for diabetic patients who may be hesitant to medically lower their blood glucose levels due to the fear of potential hypoglycaemic reactions. However, the patho-genesis of hypoglycaemic counterregulation is still unclear. Glucagon-like peptide-1 (GLP-1) and its analogues have been used as adjunctive therapies for type 1 diabetes mellitus (T1DM).
View Article and Find Full Text PDFJ Cardiovasc Pharmacol
June 2024
Department of Pharmacology, Akdeniz University Faculty of Medicine, Antalya, Turkey.
Type 2 diabetes mellitus increases the risk of cardiovascular diseases. Therefore, elucidation of the cardiovascular effects of antidiabetics is crucial. Incretin-based therapies are increasingly used for type 2 diabetes mellitus treatment as monotherapy and in combination.
View Article and Find Full Text PDFMol Biol Rep
February 2024
Department of Neurosurgery, Tangshan Gongren Hospital, Tangshan, 063000, Hebei, China.
Background: Glucagon-like peptide-1 (GLP-1) (7-36) amide, an endogenous active form of GLP-1, has been shown to modulate oxidative stress and neuronal cell survival in various neurological diseases.
Objective: This study investigated the potential effects of GLP-1(7-36) on oxidative stress and apoptosis in neuronal cells following traumatic brain injury (TBI) and explored the underlying mechanisms.
Methods: Traumatic brain injury (TBI) models were established in male SD rats for in vivo experiments.
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