Abstract
This study was performed to investigate the effect of protein intake on kidney development and function in growing rats. Fourty-two male Spraque-Dawley rats of weighing $97.5\pm1.9g$ were divided into 3 groups and given 5%, 15% or 50% casein diets for 6 weeks. Body weight gain was higher in the 50% group. The kidney weight was selectively affected more by the level of dietary protein compared to the other organs. DNA and RNA content were significantly higher in the 15% and 50% groups than in the 5% group but the differences disappeared when DNA and RNA were expressed per g of kidney weight. Protein and protein/g kidney content were increased with increasing level of protein in diet. GFR/animal and GFR/100gB. W. were significantly higher in the 50% group compared to the 5% and 15% groups. There was no differences in PAH clearence and RBF. Osmolality was not affected by dietary protein level. BUN and urinary nitrogen excretion were increased with the increasing dietary protein level. Although urinary Ca excretion was not significantly difference among 3 groups, the rats in the 5% group showed 30% less Ca excretion compared to the other groups. Above results suggest that dietary protein level has a great effect on the kidney weight and GFR in growing rats. Especially the hyperfiltration inhanced by high protein diet may accelerate the kidney senescence.
본 연구에서는 식이단백질 수준이 성장기 흰쥐의 신장 발달과 기능에 미치는 영향을 조사하기 위해 평균체중이 97.5$\pm$1.9g인 숫컷 흰쥐를 5%, 15% 그리고 50% casein 식이로 6주간 사육하였다. 체중증가량은 단백질 수준이 높을수록 높았으며 특히 단백질수준이 신장무게에 미친영향이 간, 비장, 흉선 등이 다른 장기에 비해 컸다. 신장내 총 DNA와 RNA 함량에서는 유의적인 차이가 없었다. 총 protein과 단위 g당 protein 함량은 식이내 단백질수준이 높을 수록 증가했다. 사구체여과율(GFR)은 식이단백질 수준이 높을수록 높았으나 신혈류(RBF)는 각 군 사이에 유의적인 차이를 보이지 않았다. 뇨질소배설량은 단백질 수준에 비례하여 유의적인 차이를 보였고 노칼슘배설량은 5%군이 낮은 경향을 보였다. 본 연구 결과로 성장기의 흰쥐에서 고단백식이는 신장의 무게증가를 촉진하며 사구체여과율을 증가시킴을 알 수 있다.