The Glucose Tolerance Test in Mice

Type 2 diabetes is characterized by glucose intolerance, caused by insulin resistance in peripheral metabolic tissues and by impaired glucose-stimulated insulin secretion, the hallmark of beta-cell dysfunction. The glucose tolerance test is used in clinic and research to identify individuals with impaired glucose tolerance and overt type 2 diabetes. It is the most routinely used physiological test for first pass assessment of glucose homeostasis in rodents because of its simplicity. The GTT measures changes in blood glucose concentration over a 2-h period following the administration of a bolus of glucose. However, this simplicity belies several important considerations which need to be addressed, to aid reproducibility and produce interpretable data. Here, we describe in detail how to perform a GTT using four different routes of glucose administration: intraperitoneal, oral, voluntary oral, and intravenous.