In carcinoid syndrome, when the tumor is located in the GI tract with liver metastasis, serotonin reaches systemic circulation; if there is no liver metastasis, what is true about serotonin?

• A. Serotonin still reaches systemic circulation despite no liver involvement
• B. The liver metabolizes serotonin derivatives, preventing systemic symptoms
• C. It causes systemic symptoms only after bronchial metastasis
• D. It does not affect the heart

Answer: (B)