DPP4 and diabetes mellitus: Nauck, M (14) found that after the addition of sitagliptin to the treatment regimen of patients with diabetes with poor glucose control on oral antidiabetes drugs, it was found that the standard deviation of 24-h glucose, the 24-h mean glucose fluctuation range, and the glucose fluctuation range of patients decreased significantly.GLP-1 signaling in the central nervous system can control glucose uptake and production in peripheral tissues, and dulaglutide also plays a role through GLP-1 receptor signaling pathway (23), which may be similar to DPP4 inhibitors in keeping glucose stable.