[Type 2 diabetes and impaired glucose tolerance].

Due to the changes of lifestyle in Japan, the number of subjects with type 2 diabetes due to obesity has been increasing. Obesity usually accompanies with an increase of the size of fat cells, which causes the changes of adipokines, such as the decrease of adiponectin and the increase of TNFalpha and free fatty acids, and leads to insulin resistance. As it has been suggested that the capacity of insulin secretion in pancreatic beta cells of Japanese is lower than that of Caucasian, the Japanese likely to develop diabetes with mild obesity. In the treatment of type 2 diabetes accompanied with obesity, more strict diet therapy and exercise are required. In drug therapy of such patients, the drugs to improve insulin resistance, such as biguanides, thiazolidine derivatives, DPP-4 inhibitors and GLP-1 analogues should be selected.