Duncan J R, Hurley L S
Am J Physiol. 1978 Nov;235(5):E556-9. doi: 10.1152/ajpendo.1978.235.5.E556.
This study examined the proposal that a low molecular weight, zinc-binding ligand (ZBL) in certain milks is important for zinc absorption in the neonatal period. Ten-day-old rats, in which intestinal ZBL is absent, fed (by stomach intubation) 65Zn-labeled ZBL from rat milk, absorbed significantly more 65Zn than those fed free 65ZnCl2 or bovine milk fractions. ZBL from human milk appeared to have an intermediate effect, possibly due to species specificity. 65Zn was found in the ZBL fraction in intestinal mucosa of 10-day-old rats fed rat or human milk fractions, but not in those fed bovine milk or free 65ZnCl2. In contrast, in 18-day-old rats, which have an endogenous intestinal ZBL, there were no differences in zinc absorption, and any of the labeled milk fractions or free 65Zn caused localization of 65Zn in the ZBL fraction of intestinal mucosa. These results support the hypothesis that the intestinal ZBL plays a role in zinc absorption and that in the neonatal period before its development the milk ZBL is valuable for this function. This mechanism may be important in normal human infants as well as in acrodermatitis enteropathica patients.
本研究检验了一种观点，即某些乳汁中的低分子量锌结合配体（ZBL）对新生儿期锌的吸收很重要。肠道中缺乏ZBL的10日龄大鼠通过胃插管喂食来自大鼠乳汁的65Zn标记的ZBL，其吸收的65Zn明显多于喂食游离65ZnCl2或牛乳组分的大鼠。人乳中的ZBL似乎具有中等作用，这可能是由于物种特异性所致。在喂食大鼠或人乳组分的10日龄大鼠的肠黏膜ZBL组分中发现了65Zn，但在喂食牛乳或游离65ZnCl2的大鼠中未发现。相反，在具有内源性肠道ZBL的18日龄大鼠中，锌吸收没有差异，任何标记的乳汁组分或游离65Zn都会使65Zn定位于肠黏膜的ZBL组分中。这些结果支持了以下假设：肠道ZBL在锌吸收中起作用，并且在其发育之前的新生儿期，乳汁中的ZBL对该功能很重要。这种机制在正常人类婴儿以及肠病性肢端皮炎患者中可能也很重要。
