Gourley G R, Kreamer B L, Cohnen M
Department of Pediatrics, University of Wisconsin Medical School, Madison, USA.
J Pediatr Gastroenterol Nutr. 1997 Sep;25(3):267-72. doi: 10.1097/00005176-199709000-00005.
A casein hydrolysate infant formula has been shown to be associated with lower levels of neonatal jaundice than are standard infant formulas. Because beta-glucuronidase is related to neonatal jaundice, this study examined the effect of a casein hydrolysate formula on beta-glucuronidase.
Beta-glucuronidase activity was measured with or without added dietary components. The beta-glucuronidase sources used were meconium, breast milk, and the purified bovine liver enzyme. The dietary components assayed for their effect on beta-glucuronidase activity included casein hydrolysate formula (Nutramigen), whey-predominant formula (Enfamil), breast milk; enzymatically hydrolyzed casein, and other constituents of the casein hydrolysate formula. Stool samples of 6-day-old infants, who were exclusively fed one of the two formulas or breast milk, were also assayed for inhibition of beta-glucuronidase.
Only Nutramigen, enzymatically hydrolyzed casein, and stool from Nutramigen-fed infants consistently demonstrated significant inhibition of beta-glucuronidase activity, ranging from 45% to 85% of that in controls. The inhibition of beta-glucuronidase in purified bovine liver demonstrates a dose response in a pH range from 4 to 7.3.
Hydrolyzed casein contains a beta-glucuronidase inhibitor that, in casein hydrolysate-fed infants, persists after passage through the digestive tract. These data are consistent with the possibility that inhibition of beta-glucuronidase is a mechanism by which infants fed casein hydrolysate have lower jaundice levels than infants fed routine formulas or breast milk. Further study of this mechanism is needed.
与标准婴儿配方奶粉相比，酪蛋白水解物婴儿配方奶粉已被证明与新生儿黄疸水平较低有关。由于β-葡萄糖醛酸酶与新生儿黄疸有关，本研究检测了酪蛋白水解物配方奶粉对β-葡萄糖醛酸酶的影响。
在添加或不添加膳食成分的情况下测量β-葡萄糖醛酸酶活性。所用的β-葡萄糖醛酸酶来源为胎粪、母乳和纯化的牛肝酶。检测其对β-葡萄糖醛酸酶活性影响的膳食成分包括酪蛋白水解物配方奶粉（纽太特）、以乳清为主的配方奶粉（美赞臣安儿宝）、母乳、酶解酪蛋白以及酪蛋白水解物配方奶粉的其他成分。对仅喂养两种配方奶粉之一或母乳的6日龄婴儿的粪便样本也进行了β-葡萄糖醛酸酶抑制检测。
只有纽太特、酶解酪蛋白以及食用纽太特配方奶粉的婴儿的粪便始终显示出对β-葡萄糖醛酸酶活性有显著抑制，抑制程度为对照组的45%至85%。纯化牛肝中β-葡萄糖醛酸酶的抑制在pH值4至7.3范围内呈现剂量反应。
水解酪蛋白含有一种β-葡萄糖醛酸酶抑制剂，在食用酪蛋白水解物配方奶粉的婴儿中，该抑制剂在经过消化道后仍会存在。这些数据与以下可能性一致，即抑制β-葡萄糖醛酸酶是食用酪蛋白水解物配方奶粉的婴儿黄疸水平低于食用常规配方奶粉或母乳的婴儿的一种机制。需要对这一机制进行进一步研究。
