Oral Glucose Tolerance Test (OGTT): Measuring Glucose Metabolism in Mice

Prepare for the test by fasting the mice for 6 hours. Then, weigh each mouse to determine its body mass, which will be used to calculate the dose of glucose to be used. To measure the baseline blood glucose for each mouse, we'll use a glucometer and glucose chip, commonly known as a test strip.

Collect blood by cutting off 1 to 2 millimeters of the tail tip. Place a drop of this blood on the glucose chip and record the measurement. Next, feed glucose to the mouse by gavage and immediately record the time. Repeat the blood glucose measurements over 2 hours.

This test will monitor how much the blood glucose increases as oral glucose is taken up by the body and how quickly it returns to normal as peripheral tissues take up the glucose to be used or stored.

Before starting the glucose tolerance test, prepare the glucose solution by dissolving 3.75 grams glucose and 15 milliliters distilled water. Set up a timetable with proper intervals between each blood examination to record the readings during the experiment. Next, weigh each mouse after fasting to calculate the appropriate amount of glucose for the injection.

Then, at the workbench, prepare a timer, glucose chip, glucometer, insulin syringe, and razor blades. To measure the blood glucose level, first, insert a new glucose chip into the glucometer and press the Start button to set the zero. Then, pick up the mouse at the back of the neck and stroke its tail to ensure sufficient blood flow.

Use a new razor blade to cut off a small piece of the tail and then squeeze out a drop of blood into the glucose chip. Using intragastric gavage technique, feed the mouse glucose and immediately start the timer. Measure the glucose at different time points.