AEMCA Practice Exam

Which hormone decreases blood glucose levels?

1. Glucagon.

2. Cortisol.

3. Insulin.

4. Adrenaline.

The correct answer is: Insulin.

Insulin is the hormone that decreases blood glucose levels, playing a crucial role in regulating glucose homeostasis in the body. When blood glucose levels rise, such as after eating, the pancreas secretes insulin. This hormone facilitates the uptake of glucose by cells, particularly in muscle and fat tissues, allowing them to use glucose for energy or store it as glycogen. Additionally, insulin inhibits gluconeogenesis and the release of glucose from the liver, resulting in a decrease in overall blood glucose levels. Understanding the roles of other hormones is essential for context. Glucagon, for instance, works oppositely by increasing blood glucose levels when they are low. Cortisol, a stress hormone, can also lead to increased blood glucose levels through various mechanisms, including stimulating gluconeogenesis. Adrenaline (or epinephrine) similarly functions to elevate blood sugar by promoting glycogen breakdown in the liver and enhancing glucose release into the bloodstream during stressful situations. Thus, while these hormones play important roles in metabolism, insulin is specifically responsible for lowering blood glucose levels.