In db/db mice, empagliflozin, but not linagliptin, reduced the blood glucose level (Fig. 2B and C), probably because severe hyperglycemia with glucose toxicity decreases GLP-1 and gastric inhibitory peptide receptor expression in pancreatic β cells [25], and linagliptin did not decrease the blood glucose level. Here, GLP1R is linked to Hyperglycemia.