Which signaling molecule regulates the synthesis of antioxidant enzymes?

• A. AMPK
• B. Nuclear factor kappa B
• C. PGC-1α
• D. mTOR

Answer: (C)

PGC-1α is the key driver of antioxidant enzyme production in response to exercise and oxidative stress. It is a transcriptional coactivator that partners with factors like NRF-1/2 to ramp up the expression of antioxidant enzymes such as MnSOD (mitochondrial superoxide dismutase) and catalase. When endurance exercise raises ROS and energy demand, PGC-1α becomes activated (in part by signals like AMPK and p38 MAPK) and translates that stress into increased antioxidant defenses, helping to balance redox state as mitochondrial capacity grows. AMPK acts upstream to activate PGC-1α, rather than directly triggering antioxidant enzyme synthesis; mTOR governs general protein synthesis and growth, not specifically antioxidant enzymes; NF-κB is more about inflammatory responses and is not the primary regulator of this antioxidant program.