Satoh A, Hitomi M, Igarashi K
Department of Bioproduction, Faculty of Agriculture, Yamagata University, Tsuruoka, Japan.
J Nutr Sci Vitaminol (Tokyo). 1995 Oct;41(5):563-73. doi: 10.3177/jnsv.41.563.
The effects of spinach leaf protein concentrate (SPPC) on serum and liver lipid concentrations and on serum free amino acid concentrations were examined in rats fed a cholesterol-free diet containing 2 and 10% fats. The serum total cholesterol, triacylglycerol and phospholipid concentrations in the rats fed an SPPC diet containing 2% corn oil were significantly lower than those of the rats fed a corresponding casein diet. When 10% corn oil or lard was used, the serum cholesterol-lowering effect of the SPPC became insignificant, but the serum and liver triacylglycerol concentrations were kept at significantly lower levels. Both the amounts of fecal neutral steroids and bile acids were significantly higher in the rats fed the SPPC than those of the casein-fed rats. The concentrations of serum threonine, serine, glutamine, glycine, cystine, and isoleucine were significantly higher in the rats fed the SPPC diet containing 2% corn oil compared with those of the control rats, but when the dietary fat was raised to 10%, only glycine showed a higher serum concentration. These results indicate that the SPPC has a stronger cholesterol-lowering effect at a lower dietary fat level, 2%, and the activity is partly due to the inhibition of intestinal absorption of cholesterol and bile acid, and partly due to an increase in the concentration of some of the serum amino acids.
在喂食含2%和10%脂肪的无胆固醇饮食的大鼠中，研究了菠菜叶浓缩蛋白（SPPC）对血清和肝脏脂质浓度以及血清游离氨基酸浓度的影响。喂食含2%玉米油的SPPC饮食的大鼠，其血清总胆固醇、三酰甘油和磷脂浓度显著低于喂食相应酪蛋白饮食的大鼠。当使用10%玉米油或猪油时，SPPC的血清胆固醇降低作用变得不显著，但血清和肝脏三酰甘油浓度保持在显著较低水平。喂食SPPC的大鼠粪便中性类固醇和胆汁酸的量均显著高于喂食酪蛋白的大鼠。与对照大鼠相比，喂食含2%玉米油的SPPC饮食的大鼠血清苏氨酸、丝氨酸、谷氨酰胺、甘氨酸、胱氨酸和异亮氨酸浓度显著更高，但当饮食脂肪含量提高到10%时，只有甘氨酸的血清浓度更高。这些结果表明，SPPC在较低饮食脂肪水平（2%）时具有更强的降胆固醇作用，其活性部分归因于对胆固醇和胆汁酸肠道吸收的抑制，部分归因于某些血清氨基酸浓度的增加。
