Modeling of age-dependent disorders: relationship between the nervous and endocrine systems

Age-dependent disorders are a challenging problem of modern society. Among the most significant age-dependent disorders are Alzheimer's disease (AD), diabetes, metabolic syndrome, etc.; these conditions may be associated to each other and have, at least in part, an interconnecting character. An experimental model of AD induced by intracerebroventricular administration of streptozocin (STZ) mimics some key characteristics of sporadic AD, altering insulin metabolism. The aim of this work was to study glucose metabolism in rats at different periods after intracerebroventricular injection of STZ. To obtain an AD model, STZ in a 0.9% NaCl solution at a dose of 3 mg/kg in 10 μl was administered bilaterally in the brain lateral ventricles on stereotaxic operations. Two and seven weeks after the administration, the weight of the animals was determined, and the glucose levels in tail vein whole blood after intraperitoneal glucose administration at a dose of 1.5 g/kg was measured. A standard glucose tolerance test was performed, and hyperglycemic and postglycemic ratios were calculated. As a result, an impairment of glucose metabolism in rats 7 weeks after intracerebroventricular application of STZ was detected for the first time. Close connection of Alzheimertype neurodegenerative changes and glucose metabolism revealed on this model allows using it for deeper assessment of relationships between the nervous and endocrine systems, including translational studies of novel therapeutic strategies.