Effect of age and long-term diet on exocrine pancreas of the rat.
Effect of age and long-term diet on exocrine pancreas of the rat.
复制标题
年龄和长期饮食对大鼠外分泌胰腺的影响。
作者：
J. Snook
研究年龄和长期营养处理对胰腺组成和消化功能的影响，分别在断奶后饲喂谷物型食物（实验1）或9个月后饲喂含有30%酪蛋白、34%乳脂、54%淀粉或54%蔗糖的日粮（实验2）。在杀死大鼠之前，将大鼠适应为15%全蛋蛋白饮食1-2周。在实验1中，胰腺大小、核酸和消化酶含量随着年龄的增长而显著增加，直至3月龄。28月龄大鼠的胰腺重量和DNA值明显高于12月龄大鼠。胰腺消化酶含量在有和没有明显病理病变的大鼠中降低65-100%。在实验2中，喂食乳脂或蔗糖的大鼠在24月龄时死亡率更高，病理变化更明显。虽然胰凝乳胰蛋白酶原和胰蛋白酶原浓度与病理改变程度呈显著负相关，但胰酶的减少程度通常不如实验1。酶储备减少的大鼠对饲粮氮的表观消化率和食物能量含量不降低。老年大鼠和对照组大鼠胰腺蛋白和RNA在体外的掺入率无显著差异。
Effects of age and long-term nutritional treatment on pancreas composition and digestive function were determined in rats fed a cereal-type chow after weaning (experiment 1) or diets with 30% casein and 34% butterfat, 54% starch, or 54% sucrose after 9 mo (experiment 2). The rats were adapted for 1-2 wk to a 15% whole-egg protein diet before killing. In experiment 1, pancreas size, nucleic acid, and digestive enzyme content increased significantly with age up to 3 mo. Values for pancreatic weight and DNA were significantly greater in 28-mo-old rats than in 12-mo-old rats. Pancreatic digestive enzyme content was 65-100% lower in rats with and without gross pathologic lesions. In experiment 2, mortality was higher and pathologic changes were more pronounced by 24 mo in rats fed the butterfat or sucrose diet. Usually, pancreatic enzymes were not reduced as much as in experiment 1, although chymotrypsinogen and trypsinogen concentrations were significantly and negatively correlated with the degree of pathologic change. Apparent digestibility of dietary nitrogen and food energy content was not reduced in rats with reduced enzyme reserves. The rate of incorporation in vitro of label into pancreatic protein and RNA did not differ significantly among aged and control rats.