INS and type 2 diabetes mellitus: Upon oral administration of three different doses of INS-SeNPs (12.5, 25, or 50 IU/kg) to normal Sprague–Dawley and T2DM Goto-Kakizaki rats, the dosage of 50 IU/kg had a significant hypoglycemic effect in normal rats, similar to that of SC insulin (1 IU/kg).