The hypothalamus NPY contents were 133.4 ± 17.1 (pg/ml) in the normal control group, and were 160.9 ± 21.7, 194.8 ± 37.0, and 251.1 ± 40.9 (pg/ml), respectively in the DIO4W, DIO8W, and T2DM group. Here, NPY is linked to type 2 diabetes mellitus.