INS and Adrenal insufficiency: Laboratory tests indicated no apparent endogenous hypersecretion of insulin [serum immunoreactive insulin (IRI) 2 μU/mL, C-peptide immunoreactivity (CPR) 1.37 ng/mL, corresponding to the plasma glucose level of 86 mg/dL], negative insulin autoantibody, and no apparent adrenal insufficiency (morning serum adrenocorticotropic hormone 17.2 pg/mL, cortisol 10 μg/dL).