AAMC FL Practice Exam

How do glucocorticoids affect skeletal muscles?

1. They promote muscle growth

2. They cause protein breakdown in muscles

3. They enhance muscle recovery

4. They hinder muscle metabolism

The correct answer is: They cause protein breakdown in muscles

Glucocorticoids are steroid hormones that have a significant impact on various metabolic processes in the body, including muscle tissue. One of their primary effects on skeletal muscles is the promotion of protein catabolism, which leads to protein breakdown. When glucocorticoids are present in elevated levels, they facilitate the degradation of muscle proteins, thereby diminishing muscle mass and strength. This is particularly evident during instances of prolonged stress or inflammation when glucocorticoid levels are elevated. This destructive process occurs as glucocorticoids increase the expression of certain enzymes that break down proteins in muscle tissue while inhibiting the pathways that promote muscle growth and repair. As a result, long-term exposure to elevated glucocorticoids can lead to muscle wasting, contributing to a reduction in overall muscle mass.