Schwarz F J, Kirchgessner M, Roth H P
Res Exp Med (Berl). 1983;182(1):39-48. doi: 10.1007/BF01852286.
The influence of the ligands picolinic acid and citric acid on the intestinal absorption of zinc was studied in two different experimental trials with Zn-depleted and Zn-supplied pair-fed rats using everted sacs in vitro and the ligated small intestine in vivo. ZnSO4 was applied in water solution (pH 5.8) without ligands or together with picolinic acid at a molar ratio of 1:0.2, 1:2, and 1:20 or together with citric acid at a molar ratio of 1:1, 1:10, and 1:100. The intestinal Zn transfer of the Zn-depleted rats with picolinic acid is significantly increased only at a molar ratio of 1:20 (zinc:ligand) (P less than 0.001). The other in vitro results of Zn absorption were only slightly improved, mainly at the high molar excess of picolinic acid in comparison to ZnSO4 without ligands. Only a tendency for an increased Zn transfer--however, already at a narrow molar ratio of 1:1 or 1:10--could be seen when citric acid was added. The intestinal uptake was not influenced by citric acid. The absorption of zinc in vivo did not vary in dependence of the addition of picolinic or citric acid in different molar ratio in comparison to ZnSO4 addition without ligands. Zn-depleted rats showed a significantly higher Zn absorption rate than Zn supplied pair-fed rats independently of the kind of ligand and the zinc:ligand ratio (P less than 0.001). These results are discussed in detail.
在两项不同的实验中，使用体外翻袋法和体内小肠结扎法，对缺锌和补锌的成对喂养大鼠研究了吡啶甲酸和柠檬酸配体对锌肠道吸收的影响。硫酸锌以水溶液（pH 5.8）形式施用，不添加配体，或与吡啶甲酸以1:0.2、1:2和1:20的摩尔比混合，或与柠檬酸以1:1、1:10和1:100的摩尔比混合。缺锌大鼠与吡啶甲酸一起时，仅在锌:配体摩尔比为1:20时肠道锌转运显著增加（P小于0.001）。锌吸收的其他体外结果仅略有改善，主要是在吡啶甲酸相对于无配体硫酸锌的高摩尔过量情况下。添加柠檬酸时，仅在1:1或1:10的狭窄摩尔比下可观察到锌转运增加的趋势。肠道摄取不受柠檬酸影响。与添加无配体硫酸锌相比，体内锌的吸收并不因添加不同摩尔比的吡啶甲酸或柠檬酸而有所不同。缺锌大鼠显示出比补锌成对喂养大鼠显著更高的锌吸收率，与配体种类和锌:配体比例无关（P小于0.001）。对这些结果进行了详细讨论。
