长期蛋白饲养对正常大鼠葡萄糖刺激的胰岛素分泌的影响

目的：观察总热量正常、不同含量蛋白质饮食长期饲养对正常大鼠葡萄糖刺激的胰岛素分泌的影响。方法：选择8周龄健康雄性Wistar大鼠51只，分普通饲养组（NC，n=16）、高蛋白饲养组（HP,n=19）、低蛋白饲养组（LP,n=16）3组，各组大鼠日摄入总热量相同，共饲养24周。饲养期间，观察大鼠体重、空腹血糖（FBG）、空腹胰养岛素（FINS）水平的变化。于32周龄时，行静脉葡萄糖耐量试验（IVGTT），观察各组大鼠葡萄糖刺激的胰岛素分泌，尤其是胰岛素分泌第一时相的差异。结果：与NC组比较，HP组及LP组的体重和内脏脂肪重量、IVGTT各点血糖均无显著差异，HP组5min、10min血清胰岛素水平显著升高［(6.5±0.8)ng/ml vs (4.9±0.7)ng/ml,P＜0.001;(3.9±0.6)ng/ml vs (3.1±0.5)ng/ml,P＜0.001］，而LP组无显著差异。结论：长期高蛋白饲养大鼠第一时相胰岛素分泌显著升高，低蛋白饲养大鼠胰岛素分泌则无明显改变。

Effect of long-term dietary protein feeding on glucose-stimulated insulin secretion in normal rats

Objective: To investigate the effects of long-term protein diet with normal total calorie intake on glucose-stimulated insulin secretion in normal rats. Methods: 51 healthy male Wistar rats (8 weeks old) were selected and divided into three groups: the routine feed group (NC, n=16), the high protein diet group (HP, n=19) and the low protein diet group (LP, n=16). The total calorie ingestion of each rat per day was similar and was used for 24 weeks. Body weight, fasting blood glucose (FBG) and fasting plasma insulin (FINS) were monitored during feedings. The insulin secretary function of β cells, especially the acute insulin response(AIR) were determined by the intravenous glucose tolerance test (IVGTT) in 32-week-old rats. Results: 1. Body weight and visceral fat mass: Compared with the NC group, there were no differences of the HP or LP groups. 2. IVGTT: (1) Blood glucose: There were no differences among the three groups. (2) Plasma insulin: 5min- and 10min- plasma insulin levels were markedly higher in the HP group than in the NC group［(6.5±0.8)ng/ml vs (4.9±0.7)ng/ml, P＜0.001; (3.9±0.6)ng/ml vs (3.1±0.5)ng/ml, P＜0.001］, and there were no differences between the LP and NC groups. Conclusion: The long-term high protein ingestion with total calorie may significantly enhance the AIR by IVGTT in rats, while low protein intakes has not significant effect on insulin secretion in rats.