蛋白質 最低要求量 測定에 관한 硏究

Abstract

本 硏究에서는 한국여대생의 단백질 최저요구량 및 흰쥐에 있어 탄수화물 섭취량이 단백질 최저요구량에 미치는 영향을 알아 보고져 二部分으로 나누어 실험하였다. 제Ⅰ실험에서는 3名의 이화여자대학교 대학생을 실험대상으로 체중을 유지할 만큼 열량이 충분한 무단백식이를 7일간 섭취시켜, 尿, 대변, 피부를 통한 질소 배설량을 測定하여 蛋白質 최저 요구량을 구하였으며, 제Ⅱ실험에서는 生後 50日정도로 체중이 120g인 흰쥐 암컷 15마리로 탄수화물 섭취량이 蛋白質 要求量에 미치는 영향을 알아 보고져 三部分으로 나누어 실험 2 - 1에서는 무단백식이를 9일간 섭취시켜 흰쥐의 단백질 최저요구량을 구하였으며, 실험 2 - 2에서는 흰쥐의 단백질 최저 요구량을 중심으로 7일간 3단계로 다른 양의 Casein을 주어 the least squares regression method 를 이용하여 질소 평형을 유지시킬수 있는 Casein의 최저요구량을 정하였으며, 실험 2-3에서는 7일간 Casein의 최저요구량을 동일하게 주고 3단계로 탄수화물의 섭취량을 달리하였을때 질소균형에 어떠한 영향을 미치나 살펴보았다. 위의 실험결과는 다음과 같다. 제Ⅰ실험 무단백식이를 섭취한 3名의 여대생의 최저 체내질소 배설은 尿을 통하여 1.89g , 대변으로 1.10g, 피부를 통하여 0.0108g이였다. 1日 최저 체내질소 배설량은 3.0g이고 1日 평균 질소섭취량이 0.52g이므로 이들의 1日 질소 최저요구량은 2.48g이였다. 제Ⅱ실험 실험 2 - 1 : 무단백식이를 섭취할 흰쥐의 최저 체내질소 배설량은 尿 질소 22.63±0.84mg, 대변 질소 13.12±0.47mg으로 35.71±1.27mg이었다. 따라서 흰쥐의 1日 단백질 최저요구량은 225mg이었다. 실험 2 - 2 : 흰쥐에 있어 질소평형을 유지시킬 수 있는 1日 Casein의 최저요구량은 340mg이었다. 실험 2 - 3 : 1日 7% Casein식이 5g(350mg Casein)을 동일하게 주고 Sugar-CornstarchMixture로 탄수화물 섭취량을 12Kcal, 26Kcal, 46Kcal로 달리하였을때, 질소균형이 각각 +0.0021,+0.0073,+0.0143으로 3 group간에 유의적인 차가 있었다.;This study was carried out to estimate the minimum protein requirement for the Korean college girls, and to see the effect of carbohydrate intake on the minimum protein requirement in the rat. In the first, experiment, three students attending Ewha Womens University were given protein free diet for 7 days while caloric intake were adjusted, to maintain constant body weight. Endogenous nitrogen excretion was measured, to estimate their minimum protein requirement. Second experiment, was carried out in 3 parts to find oat the effect of carbohydrate intake on the minimum protein requirement using 15 female, 50 day old rats weighing 120 g. In experiment, 2-1, the rats were fed protein free diet tor 9 days and endogenous nitrogen excretion was measured to determine the minium protein requirement of the rats. In experiment 2-2, the minium casein requirement, of the rats needed to maintain nitrogen equilibrium was estimated by the least squares regression method feeding 3 different levels of casein, determined from the result of experiment 2-1. Finally, in experiment 2-3, the rats were given the minimum casein requirement to 7 days with 3 different levels of carbohydrate intake on the nitrogen balance. The results of this study were as follows. Experiment. I Daily endogenous nitrogen losses of 3 college girls were 1.89g in urine, 1.10g in feces and 0.0108g from skin since the total daily endogenous nitrogen loss was 3.0g and the total daily nitrogen intake was 0.52g, the minimum nitrogen requirement of these subjects was about 2.48g/day(15.5g protein/day) Experiment II. Experiment 2-1: daily endogenous nitrogen losses of the rats fed protein free diet were 22.63±0.84mg through urine and 13.12±0.47mg in feces. The total daily endogenous nitrogen output was 35.71±1.27mg and the minimum protein requirement of the rats was 225mg/day in this study. Experiment. 2-2 : the minimum, casein requirement needed to maintain the rats in nitrogen equilibrium was determined to be 340 mg/day. Experiment 2-3 : the rats were given 350 mg/day casein with 3 different, levels of carbohydrate (12.26 or 46 Cal by sugar-cornstarch mixture). The nitrogen balances were measured to be +0.0021, +0.0073 and +0.0143 respectively and there were significant differences among 3 groups.