GLP1R and Hyperglycemia: Furthermore, other studies demonstrated that acute GIP infusion to human would increase adipose tissue blood flow [46], promote insulin sensitivity, glucose tolerance and β-cell function [45]. A hyperglycemic clamp study has found that GLP-1R expression decreased but GIP R expression increased under the effect of acute hyperglycemia, and is similar with the experimental results of culturing at high-glucose concentrations for 48 hours [47].