Physiology The rate-limiting step in the synthesis of cortisol is catalyzed by: A 21-Hydroxylase B 3b-Hydroxysteroid dehydrogenase C Cholesterol side-chain cleavage enzyme D 11b-Hydroxylase 💡 Explanation The rate-limiting step in the synthesis of cortisol is catalyzed by: ✓ Correct Answer: C. Cholesterol side-chain cleavage enzyme