Nagai K, Thibault L, Nishikawa K, Hashida A, Ootani K, Nakagawa H
Division of Protein Metabolism, Osaka University, Japan.
Brain Res Bull. 1991 Sep-Oct;27(3-4):409-15. doi: 10.1016/0361-9230(91)90134-6.
The effect of glucagon on macronutrient selection was studied using rats. Continuous infusion of glucagon (5 ng/microliters/h) into the lateral cerebral ventricle increased total caloric intake and protein selection, and decreased carbohydrate selection. Continuous infusion of glucagon subcutaneously induced similar changes. Since a hyperglycemic response to the intracranial injection of 2-deoxy-D-glucose (2DG) disappeared in rats either with bilateral lesions of the hypothalamic suprachiasmatic nucleus (SCN) (17) or with acquired (21) and congenital (10) blindness, and bilateral lesions of the SCN eliminated the hyperglucagonemic response to the 2DG-injection (19), changes in the plasma glucagon concentration after 2DG injection were examined in acquired and congenital blind rats. Consequently, it was found that the hyperglucagonemic response to 2DG was not observed in those blind rats which lacked the hyperglycemic response. In those SCN-lesioned and blind rats lacking the hyperglucagonemic response to 2DG, the protein selection was lower, and carbohydrate selection tended to be higher, than those selections found in the control rats. Considering the neural connection between the retina and the SCN, these findings suggest that glucagon may have a stimulatory effect on protein intake and a suppressive one for carbohydrate intake; and that the SCN may be involved in such a regulatory mechanism of feeding behavior through controlling the blood glucagon level.
利用大鼠研究了胰高血糖素对常量营养素选择的影响。向大鼠侧脑室持续输注胰高血糖素（5纳克/微升/小时）会增加总热量摄入和蛋白质选择量，并减少碳水化合物选择量。皮下持续输注胰高血糖素也会引发类似变化。由于下丘脑视交叉上核（SCN）双侧受损的大鼠（17）、后天性失明（21）和先天性失明（10）的大鼠对颅内注射2-脱氧-D-葡萄糖（2DG）的高血糖反应消失，且SCN双侧受损消除了对2DG注射的高胰高血糖素反应（19），因此研究了后天性和先天性失明大鼠注射2DG后血浆胰高血糖素浓度的变化。结果发现，在那些缺乏高血糖反应的失明大鼠中未观察到对2DG的高胰高血糖素反应。在那些对2DG缺乏高胰高血糖素反应的SCN受损且失明的大鼠中，蛋白质选择量低于对照大鼠，碳水化合物选择量则倾向于高于对照大鼠。考虑到视网膜与SCN之间的神经联系，这些发现表明胰高血糖素可能对蛋白质摄入有刺激作用，对碳水化合物摄入有抑制作用；并且SCN可能通过控制血液中胰高血糖素水平参与这种进食行为的调节机制。
