How does cortisol primarily affect metabolism?

• A. It decreases cholesterol levels
• B. It promotes muscle gain
• C. It increases glucose availability and promotes fat breakdown
• D. It inhibits insulin production

Answer: (C)

Cortisol is a crucial hormone produced by the adrenal glands in response to stress and low blood glucose levels, and it plays a significant role in regulating various metabolic processes. One of its primary effects is to increase glucose availability in the bloodstream. This is accomplished through several mechanisms; for instance, cortisol stimulates gluconeogenesis, which is the process of producing glucose from non-carbohydrate sources, primarily in the liver.

Additionally, cortisol promotes lipolysis, the breakdown of fats, which further increases the availability of fatty acids as an energy source. By mobilizing energy stores and ensuring that glucose is readily available, cortisol helps the body to respond to stress or fasting conditions effectively.

This role of cortisol in promoting both glucose availability and fat breakdown makes it essential for maintaining energy homeostasis and for the adaptation during periods of stress or increased demand. Hence, the correct choice emphasizes cortisol's dual action of enhancing glucose levels and supporting fat metabolism.