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Factors affecting the intestinal absocption of orally-given proteins in rats

影响大鼠口服蛋白质肠道吸收的因素

基本信息

批准号：
06454083
负责人：
KAKINUMA Atsushi
金额：
$ 4.67万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06454083/
关键词：
Intestunal absorption of proteins Serratia protease Orally-available anti-inflammatory protease Intestinal absorption of serratia protease Physiologically active proteins Effects of age on intertinal absorption of proteins Effects of feeding o

项目摘要

Orally given proteins are usually absorbed into body after once they are digested to amino acide or small peptides by proteolytic enzymes in the intestinal tract. However, our observation that Serratia protease (SP,MW 50,600) administered orally to scalded rats dramatically repressed the enhancement of fibrinolysis and blood vessel permeability both induced by the scalding strongly suggested its intestinal absorption. The present investigation was undertaken to make clear whether it is absorbed or not, and to identify any physiological nutritional factors that may control the degree of its intestinal absorption.We first established a highly-sensitive EIA and a protease assay for determining SP concentration in rat plasma. The SP concentration obtained by these two assay on respective plasma samples from SP-administered rats coincided well. This led us to the conclusion that a portion of orally-administered SP was absorbed from the intestinal tract and transferred to the blood stream in … More an enzymatically active form.We then investigated the effect of age and feeding on the intestinal absorption. Four groups of rats of different age were used : 3 weeks-old (suckling), 5 weeds-old (weanling), 11 weeks-old (adult) and 75 weeks-old (aged) rats. They were fasted or provided ad libitum with a chew diet before and after SP administration. The maximum plasma concentraion was realized 1-2 hours after administration. Compared to the adult groups (3 ng/ml) other three groups all gave a higher plasma concentration. In the suckling group it reached to as high as 130 ng/ml. Feeding also remarkably affected the absorption. In the fed aged group the highest concentration was elevated to 160 ng/ml, a 10-fold increase against that of fasted aged group. These results suggest the presence of some characteristic structures and functions in the intestinal tracts of suckling rats and aged rats that enables the enhanced absorption of proteins. This enhancement might be useful as an indication of ageing. Less

口服的蛋白质通常被肠道中的蛋白水解酶消化成氨基酸或小肽后被吸收到体内。然而，我们观察到，给烫伤大鼠口服沙雷氏菌蛋白水解酶(SP，Mw 50,600)可显著抑制烫伤引起的纤溶和血管通透性的增强，强烈提示其在肠道中的吸收。本研究旨在明确其是否被吸收，并确定可能控制其肠道吸收程度的任何生理营养因素。本研究首次建立了测定大鼠血浆中SP浓度的高灵敏度EIA法和蛋白酶测定法。两种方法测定给药大鼠血浆中SP浓度的结果吻合较好。这使我们得出结论，口服给药的一部分SP从肠道吸收并转移到…的血流中更具酶活性的形式。然后我们研究了年龄和喂养对肠道吸收的影响。实验分为4组：3周龄(哺乳)、5周龄(断奶)、11周龄(成年)和75周龄(老年组)。他们在服用SP前后禁食或随意咀嚼食物。血药浓度在给药后1~2小时达最大值。与成年组(3 ng/ml)相比，其他三组的血药浓度均较高。哺乳组高达130 ng/ml，喂食对吸收也有显著影响。饲喂老年组最高浓度升至160 ng/ml，是禁食老年组的10倍。这些结果表明，乳鼠和老年大鼠的肠道中存在一些特有的结构和功能，使蛋白质的吸收得以增强。这一增强可能有助于反映年龄的增长。较少