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: Medicine
[{'content': 'For the following causes of sexual dysfunction, select the most likely clinical feature.Can be caused by high prolactin level. \nSelect and explain. \nA. loss of sexual desire, B. failure of erection with absent nocturnal penile tumescence (NPT), C. absence of emission, D. absence of orgasm with normal libido and erectile function', 'role': 'user'}, {'content': 'Answer: B \nExplanation: High prolactin level suppresses luteinizing hormone-releasing hormone (LH-RH), and can result in low plasma gonadotropin and testosterone levels. It may not be obvious on physical examination. Therapy with a dopamine agonist may lower prolactin levels and reverse impotence.', 'role': 'assistant'}]