Which organ is primarily involved in detoxification and metabolic regulation?

• A. Heart
• B. Liver
• C. Brain
• D. Lungs

Answer: (B)

Detoxification and metabolic regulation are functions most characteristic of the liver. The liver’s hepatocytes house detoxifying enzymes, especially the cytochrome P450 system, which transform drugs and toxins into more water-soluble forms for elimination. This involves two phases: Phase I reactions (oxidation, reduction, hydrolysis) and Phase II conjugation (glucuronidation, sulfation, amino acid conjugation), preparing compounds for excretion in bile or urine. Beyond detox, the liver orchestrates metabolic regulation: it stores and releases glucose (glycogen storage and gluconeogenesis), processes lipids and proteins, and participates in the urea cycle to detoxify ammonia. While the heart pumps blood, the brain governs neural activity, and the lungs handle gas exchange and filtration, none match the liver’s central role in both detoxification and broad metabolic control. Therefore, the liver is the organ primarily involved in detoxification and metabolic regulation.