To investigate the effect of Banxia Xiexin Decoction（半夏泻心汤）on the function of pancreaticβcells and Gprotein-coupled receptor kinase2（GRK2）/sweet taste receptor（STR）signaling pathway in vivo and in vitro in prediabetes，so as to provide references for clinical application of Banxia Xiexin Decoction in the prevention and treatment of prediabetes.

The obese prediabetic mouse model was prepared by using 60% high-fat diet，and the mice were randomly divided into control group，model group and Banxia Xiexin Decoction group.After continuous administration of the drug for 4 weeks，the oral glucose tolerance（OGTT）and fasting insulin levels of the mice in each group were detected.The morphology of pancreatic islets was observed under paraffin sections with hematoxylin-eosin（HE）staining，the number of pancreaticβ/αcells was detected by immunofluorescence，the expressions of taste 1 receptor member 3（TAS1R3）and GRK2 were detected by immunohistochemistry method and immunofluorescence，respectively.Western blot（WB）and RT-qPCR were employed to measure the protein and mRNA expressions of TAS1R3 and GRK2 in pancreatic tissue.INS-1 pancreaticβcells were applied to be treated with Banxia Xiexin Decoction-containing serum and/or high glucose（25 mmol/L）for 24 h.Insulin secretion was detected by ELISA under low and high glucose stimulation，while the protein expressions of TAS1R3 and GRK2 were by WB.

Compared with the model group，Banxia Xiexin Decoction group exhibited a significant weight loss effect（P<0.001）.In comparison with the control group，the model group showed elevated blood glucose at each time point of OGTT，as well as the area under the glucose curve，and fasting insulin levels（P<0.01）；also the volume of islets increased，and theβ/αratio decreased significantly.The expression of TAS1R3 was down-regulated，while GRK2 expression was up-regulated.After the treatment of Banxia Xiexin Decoction，the blood glucose，the area under the blood glucose curve of OGTT and the fasting insulin level of the mice were significantly decreased（P<0.01）.The morphology and structure of islets were more regular，the volume of islets decreased，and the number of islet cells was close to that of normal islets.Banxia Xiexin Decoction restored the expression of TAS1R3 and down-regulated GRK2 expression.In vitro experiments also demonstrated that Banxia Xiexin Decoction could restore the insulin secretion disorder induced by high glucose，up-regulate the expression of TAS1R3 and down-regulate GRK2 expression.

Banxia Xiexin Decoction can effectively regulate blood glucose，protect pancreatic isletβcell function and treat prediabetes.The mechanism of action may be related to its regulation of sweet taste receptor signaling pathway ofβcells.