GCG and type 2 diabetes mellitus: Two hours after intramuscular injection of Ad-GLP-1-hUC-MSCs and Ad-GFP-hUC-MSCs, the GLP-1 content in the serum of Ad-GLP-1-hUC-MSC mice began to increase and peaked at 8 hours, indicating that Ad-GLP-1-hUC-MSCs can be efficiently secreted in type 2 diabetic mice.