Gannon M C, Nuttall F Q
Metabolic Research Laboratory, V.A. Medical Center, Minneapolis, MN, USA.
J Nutr. 1995 May;125(5):1159-66. doi: 10.1093/jn/125.5.1159.
In a previous study, administration of casein hydrolysate to food-deprived rats at a dose of 4 g/kg body wt resulted in an increase in portal plasma glucagon concentration. This was associated with an activation of phosphorylase a and a decrease in hepatic glycogen concentration. The present study was undertaken to determine whether similar results would be obtained with smaller doses. Doses of 1 and 2 g/kg body wt were administered to food-deprived rats. At a dose of 2 g/kg, portal plasma glucagon concentration was significantly elevated. This was associated with a slight increase in phosphorylase a activity (P < 0.05) and a 50% decrease in hepatic glycogen concentration (P < 0.01). At a dose of 1 g casein hydrolysate/kg body wt, changes in portal plasma glucagon concentration, phosphorylase a activity and hepatic glycogen concentration generally were not observed. Hepatic glucose, uridine diphosphoglucose, ATP and glucose-6-phosphate concentrations were unaffected by either dose of casein hydrolysate. The data indicate a dose-response relationship between casein hydrolysate administration and effects on glycogen metabolism in the liver. Protein-induced glycogenolysis is likely to occur when rats ingest a moderate amount of a pure protein meal.
在先前的一项研究中，以4 g/kg体重的剂量给饥饿的大鼠施用酪蛋白水解物，导致门静脉血浆胰高血糖素浓度升高。这与磷酸化酶a的激活以及肝糖原浓度的降低有关。本研究旨在确定较小剂量是否会得到类似结果。将1 g/kg体重和2 g/kg体重的剂量施用于饥饿的大鼠。在2 g/kg的剂量下，门静脉血浆胰高血糖素浓度显著升高。这与磷酸化酶a活性略有增加（P<0.05）以及肝糖原浓度降低50%（P<0.01）有关。在1 g酪蛋白水解物/kg体重的剂量下，未观察到门静脉血浆胰高血糖素浓度、磷酸化酶a活性和肝糖原浓度的变化。两种剂量的酪蛋白水解物均未影响肝葡萄糖、尿苷二磷酸葡萄糖、ATP和葡萄糖-6-磷酸的浓度。数据表明酪蛋白水解物的施用与对肝脏糖原代谢的影响之间存在剂量反应关系。当大鼠摄入适量的纯蛋白质餐时，可能会发生蛋白质诱导的糖原分解。
