Recent Progress in the Use of Glucagon and Glucagon Receptor Antagonists in the Treatment of Diabetes Mellitus

Glucagon is an important pancreatic hormone, released into blood circulation by alpha cells of the islet of Langerhans. Glucagon induces gluconeogenesis and glycogenolysis in hepatocytes, leading to an increase in hepatic glucose production and subsequently hyperglycemia in susceptible individuals. Hyperglucagonemia is a constant feature in patients with T2DM. A number of bioactive agents that can block glucagon receptor have been identified. These glucagon receptor antagonists can reduce the hyperglycemia associated with exogenous glucagon administration in normal as well as diabetic subjects. Glucagon receptor antagonists include isoserine and beta-alanine derivatives, bicyclic 19-residue peptide BI-32169, Des-His1-[Glu9] glucagon amide and related compounds, 5-hydroxyalkyl-4-phenylpyridines, N-[3-cano-6- (1,1 dimethylpropyl)-4,5,6,7-tetrahydro-1-benzothien-2-yl]-2-ethylbutamide, Skyrin and NNC 250926. The absorption, dosage, catabolism, excretion and medicinal chemistry of these agents are the subject of this review. It emphasizes the role of glucagon in glucose homeostasis and how it could be applied as a novel tool for the management of diabetes mellitus by blocking its receptors with either monoclonal antibodies, peptide and non-peptide antagonists or gene knockout techniques

Study on a Titanate Film and Its Photocathodic Protection Effect on 403 Stainless Steel

TiO2 and titanate semiconductor nanomaterials have attracted tremendous interest due to their exceptional electronic and mechanical properties. In the present work, a titanate nanowire network film was prepared by a combined sol-gel and hydrothermal method. The morphology, chemical composition and photoelectrochemical behavior of the film were characterized by scanning electron microscopy, X-ray diffraction, and electrochemical techniques, respectively. The results showed that the titanate film exhibited a special three-dimensional porous structure composed of titanate nanowires. When the 403 stainless steel in a 0.5 M NaCl solution was coupled to the titanate film as a photoanode in a 1.0 M NaOH solution under illumination, its potential decreased by about 570 mV, indicating the film produced a good photocathodic protection effect for the steel. EIS measurements revealed that the charge transfer resistance of the electrochemical reaction process for the steel coupled to the titanate film decreased considerably