What is an example of negative feedback in endocrine regulation?

• A. Insulin release in response to elevated blood glucose, which lowers glucose and reduces further insulin release.
• B. Glucagon release in response to low blood glucose.
• C. Adrenaline release during stress leading to increased heart rate.
• D. Oxytocin release during labor.

Answer: (A)

Negative feedback in endocrine regulation is when a change in a controlled variable triggers a response that counteracts that change, bringing the system back toward normal.

Insulin release in response to elevated blood glucose is the clearest example. When glucose rises after a meal, the pancreas secretes insulin, which promotes uptake and storage of glucose, lowering blood glucose. As the level falls, the stimulus for insulin release diminishes, so less insulin is produced. This self-lailing brake on the response precisely embodies negative feedback.

The other options depict responses that do not dampen the initial change in the same way. Adrenaline increasing heart rate is part of a rapid stress response that actively promotes arousal rather than turning off the trigger. Oxytocin release during labor is a classic positive feedback loop, where the response tends to amplify the original stimulus. Glucagon release in response to low blood glucose aims to raise glucose, which is part of restoring balance, but the scenario as stated doesn’t illustrate the self-limiting feedback as clearly as the insulin example.