During a glucose tolerance test, how do glucose levels typically behave in a diabetic animal?

• A. Show an initial peak and then diminish to normal
• B. Remain high throughout the test
• C. Show a delayed peak at the end of the test period
• D. Show below normal levels throughout the test

Answer: (B)

During a glucose tolerance test, the body is challenged with a glucose load and how quickly blood glucose returns to normal is measured. In a diabetic animal, insulin action is impaired or insufficient, so tissues don’t take up glucose effectively. As a result, blood glucose stays elevated throughout the test instead of returning toward baseline. This persistent hyperglycemia reflects the body's reduced ability to clear the glucose load.

Why the other patterns don’t fit: a normal animal would show a rise after the load but then return toward baseline as insulin promotes uptake; a delayed peak or consistently below-normal levels aren’t typical of diabetes during a tolerance test.