题目

取正常小鼠，每天饲喂一定量的甲状腺激素，3周后，该小鼠（　　）                   A．新陈代谢增强，促甲状腺激素含量增加                                               B．新陈代谢增强，促甲状腺激素含量减少                                               C．新陈代谢减弱，促甲状腺激素含量增加                                               D．新陈代谢减弱，促甲状腺激素含量减少                                               答案：解：                                                                                                    A、每天饲喂一定量的甲状腺激素，使得小鼠体内的甲状腺激素含量过多，甲状腺激素会抑制下丘脑和垂体分泌相应的激素．故A错误．                                                                                  B、甲状腺激素促进代谢活动和中枢神经系统的发育，提高神经系统的兴奋性．甲状腺激素含量过多，会抑制下丘脑和垂体分泌相应的激素．故B正确．                                                                   C、甲状腺激素促进代谢活动．而含量过多，会抑制下丘脑和垂体分泌相应的激素．故C错误．               D、甲状腺激素促进代谢活动和中枢神经系统的发育，提高神经系统的兴奋性．故D错误．               故选B．                                                                                            

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