Glucose Tolerance Testing (GTT)
The glucose tolerance test is given to determine the rate at which a mouse metabolizes sugars by stimulating insulin secretion. The test can be used to identify diabetes, insulin resistance, hypoglycemia, acromegaly, or other metabolic disorders.
Mice are fasted overnight (~14 hours), then injected via the intraperitoneal cavity with 10% glucose in PBS at a dose of 2 grams glucose per kilogram body weight. Plasma glucose is monitored prior to glucose injection and again at 30, 60, 120, and 240 minutes after injection. Glucose values are normalized to percent initial glucose by calculating the ratio of challenge values versus pre-challenge values at each time point. The percentage decrease in glucose between each time point is then calculated. In the case of baseline timepoint 0 and timepoint 30, the equation would be: % glucose disposed = [(glucoset=0 glucoset=30)/glucose t=0] x 100.