Raul F, Goda T, Gossé F, Koldovský O
Institut National de la Santé ét de la Recherche Medicale, Unité 61, Strasbourg, France.
Biochem J. 1987 Oct 15;247(2):401-5. doi: 10.1042/bj2470401.
The short-term effects of high-protein/low-carbohydrate diet on aminopeptidase N activity were studied in the brush-border membranes of proximal jejunum and proximal ileum of adult rats. The animals were starved overnight and re-fed for 15 h either with a standard diet (20% protein, 55% carbohydrate, in terms of energy content) or with a high-protein/low-carbohydrate diet of equal energy content (70% protein, 5% carbohydrate). All rats consumed similar amounts of diet, and measurements were made 15 h after initiation of re-feeding. In the proximal jejunum a slight increase in aminopeptidase activity was observed after the high-protein intake. In contrast, considerable stimulation (52%) of the enzyme specific activity was obtained in the proximal ileum. This increase in ileal aminopeptidase activity was more prominent in the mature cells of the upper villus. To determine if the increase of aminopeptidase activity was due to an increased amount of enzyme protein, rocket immunoelectrophoresis was performed with detergent-solubilized brush-border protein from ileum on agarose gels containing anti-(rat brush-border) antiserum. When the same amount of enzyme activity was loaded on the gels, the peaks of immunoprecipitate for aminopeptidase were similar for animals fed on a standard or a high-protein diet. When the same amount of protein was loaded, the peak of immunoprecipitate for aminopeptidase was higher (81%) after a high-protein diet. These results showed that the high protein intake evoked an increase in aminopeptidase activity, with a concomitant increase in the amount of immunoreactive protein.
研究了高蛋白/低碳水化合物饮食对成年大鼠空肠近端和回肠近端刷状缘膜中氨肽酶N活性的短期影响。动物禁食过夜，然后用标准饮食（按能量含量计，20%蛋白质，55%碳水化合物）或等能量含量的高蛋白/低碳水化合物饮食（70%蛋白质，5%碳水化合物）再喂养15小时。所有大鼠摄入的饮食量相似，并在再喂养开始15小时后进行测量。在空肠近端，高蛋白摄入后观察到氨肽酶活性略有增加。相比之下，回肠近端的酶比活性得到了显著刺激（52%）。回肠氨肽酶活性的增加在上部绒毛的成熟细胞中更为明显。为了确定氨肽酶活性的增加是否是由于酶蛋白量的增加，用含有抗（大鼠刷状缘）抗血清的琼脂糖凝胶对来自回肠的经去污剂溶解的刷状缘蛋白进行火箭免疫电泳。当在凝胶上加载相同量的酶活性时，标准饮食或高蛋白饮食喂养的动物氨肽酶免疫沉淀物的峰值相似。当加载相同量的蛋白质时，高蛋白饮食后氨肽酶免疫沉淀物的峰值更高（81%）。这些结果表明，高蛋白摄入引起氨肽酶活性增加，同时免疫反应性蛋白量也增加。
