This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Biochemistry
[{'content': 'G-proteins act as: \nSelect and explain. \nA. Hormone carriers, B. Hormone receptors, C. Second messengers, D. Signal transducers', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D. Signal transducersG- proteins are signal transducers. Signaling event is terminated when the hormone is removed and the a-subunit inactivates itself by converting its bound GTP to GDP.', 'role': 'assistant'}]