What effect does epinephrine have on metabolism?

• A. It decreases metabolic rate
• B. It enhances metabolic rate and heat production
• C. It has no effect on metabolism
• D. It solely regulates blood calcium levels

Answer: (B)

Epinephrine plays a crucial role in enhancing metabolism and increasing heat production, particularly in response to stress or excitement, which aligns with its function in the body's "fight or flight" response. When epinephrine is released, it stimulates processes such as glycogenolysis, where glycogen is broken down into glucose for quick energy, and lipolysis, which breaks down fats to release fatty acids. These actions lead to an increase in the availability of energy substrates, thereby elevating the metabolic rate.

Additionally, epinephrine boosts cardiac output and increases blood flow to skeletal muscles, which supports heightened metabolic activity during physical exertion. The increase in heat production, or thermogenesis, also results from heightened metabolic processes, further illustrating the hormone's impact on overall metabolism. Thus, the enhancement of metabolic rate and heat production accurately reflects the physiological effects of epinephrine in the body.