Introduction: The effect of beta3-adrenergic receptor agonists on beta cells in the islets of Langerhans is not yet clear. This study examined the beta3-adrenergic receptor agonist on beta cells in the islets of Langerhans.
Methods: Obese diabetic C57BL/KsJ-db/db mice were treated with KTO-7924, a newly-developed beta3-adrenergic receptor agonist for 28-day. We analyzed plasma parameters, insulin resistance, and insulin-positive areas among beta-cells in the islets of Langerhans.
Results and conclusion: After a 28-day oral administration period, plasma levels of hemoglobin (Hb) A1c, glucose, triglyceride (TG), and free fatty acid (FFA) were all significantly reduced in KTO-7924 treatment groups compared with controls. Plasma adiponectin levels decreased with age in the control group, but were significantly higher in a treatment group throughout the study period. Furthermore, sequential administration of KTO-7924 led to an improvement in insulin resistance in the OGTT (Oral glucose tolerance test (OGTT)), and an increase in the percentage of insulin-positive areas among beta-cells in the islets of Langerhans compared with controls. This is the first study to show islet histology after treatment of a beta3-adrenergic receptor agonist, and reveals that KTO-7924 reduces hyperglycemia, and protects beta-cells in the islets of Langerhans of db/db mice.