赖氨酸、苯丙氨酸、酪氨酸和缬氨酸对大鼠回肠锌吸收动力学作用的研究

用原位灌流的大鼠回肠研究了赖氨酸、苯丙氨酸、酪氨酸和缬氨酸对锌吸收动力学的作用。赖氨酸对大鼠回肠锌吸收动力学常数以及快速相和慢速相半衰期、回肠锌吸收率均无影响。苯丙氨酸、酪氨酸和缬氨酸能增加回肠锌吸收率。其中苯丙氨酸组K_921)、K_(12)、K_(02)的值均高于对照组。缬氨酸组K_(21)和K_(12)值高于对照,并且快速相T_(1/2)缩短。酪氨酸组K_(21)值较对照组高,而K_(12)、K_(02)值以及快速相、慢速相半衰期无改变。本研究的结果提示:苯丙氨酸、酪氨酸、缬氨酸能促进锌在大鼠回肠的吸收。氨基酸对锌吸收的促进作用与其对锌的配合物稳定常数有关。

EFFECTS OF LYSINE, PHENYLALANINE, TYROSINE, AND VALINE ON THE KINETICS OF ZINC ABSORPTION IN ILEUM OF RAT

The results of lysine, phenylalanine, tyrosine, and valine on kinetics of zinc absorption in rat ileurn using a two-compartment in situ perfusion model showed; 1. Phenylalanine can increase the zinc absorption micro-constants K21, K12, and K02, That is to say phenylalanine increases the a-mount of zinc from lumen to mucosa, from mucosa to lumen, and from mu-cosa to blood. Tyrosine and valine can increase the values of K21, so more zinc flows from lumen to mucosa; 2. The results of amino acids on the half times of zinc absorption showed that phenylalanine decreases both the half times of the fast phase and the slow phase, while valine decreases only the half time of the fast phase. Lysine and tyrosine have no effects on the half times of zinc absorption. The results of this study indicate that phenylalanine, tyrosine, and valine increase zinc absorption in the ileum of rat. The enhancing effects of amino acids on zinc absorption are related to the stability constants of zinc-amino acid chelators.