Polakof Sergio, Míguez Jesús M, Soengas José L
Laboratorio de Fisioloxía Animal, Facultade de Bioloxía, Edificio de Ciencias Experimentais, Universidade de Vigo, E-36310 Vigo, Spain.
Am J Physiol Regul Integr Comp Physiol. 2008 Aug;295(2):R478-89. doi: 10.1152/ajpregu.00176.2008. Epub 2008 Jun 4.
We hypothesize that variations in dietary carbohydrate levels produce changes in glucosensor parameters in previously characterized glucosensing areas (hypothalamus and hindbrain) related with the regulation of food intake of a carnivorous fish species like rainbow trout. Therefore, we fed trout with standard, carbohydrate-free (CF) or high-carbohydrate (HC) diets for 10 days to assess changes in glucosensing system and food intake. Fish fed CF diet displayed hypoglycemia and increased food intake. Fish fed a HC diet displayed hyperglycemia and decreased food intake. Changes in food intake due to dietary carbohydrates were accompanied in hypothalamus and hindbrain of fish fed with HC diet by changes in parameters involved in glucosensing, such as increased glucose, glucose 6-phosphate, and glycogen levels and increased glucokinase (GK), glycogen synthase, and pyruvate kinase activities as well as increased GK and GLUT2 expression. All those results address for the first time in fish, despite the relative intolerance to glucose of carnivorous species, that dietary carbohydrates are important regulators of the glucosensing system in carnivorous fish, suggesting that the information generated by this system can be associated with the changes observed in food intake.
我们假设，饮食中碳水化合物水平的变化会导致先前已确定的与肉食性鱼类（如虹鳟鱼）食物摄入调节相关的葡萄糖感应区域（下丘脑和后脑）的葡萄糖感应参数发生变化。因此，我们用标准、无碳水化合物（CF）或高碳水化合物（HC）饮食喂养虹鳟鱼10天，以评估葡萄糖感应系统和食物摄入的变化。喂食CF饮食的鱼出现低血糖且食物摄入量增加。喂食HC饮食的鱼出现高血糖且食物摄入量减少。喂食HC饮食的鱼，其下丘脑和后脑因饮食碳水化合物导致的食物摄入量变化伴随着葡萄糖感应相关参数的变化，如葡萄糖、6-磷酸葡萄糖和糖原水平升高，葡萄糖激酶（GK）、糖原合酶和丙酮酸激酶活性增加，以及GK和GLUT2表达增加。尽管肉食性鱼类对葡萄糖相对不耐受，但所有这些结果首次表明，饮食中的碳水化合物是肉食性鱼类葡萄糖感应系统的重要调节因子，这表明该系统产生的信息可能与食物摄入量的变化有关。
