代谢
锌可以通过肺部、皮肤和胃肠途径进入人体。肠道对锌的吸收是由锌载体蛋白CRIP控制的。锌还与金属硫蛋白结合,帮助防止过量锌的吸收。锌在体内广泛分布,存在于所有组织和组织液中,尤其在肝脏、胃肠道、肾脏、皮肤、肺、大脑、心脏和胰腺中含量较高。在血液中,锌与红细胞中的碳酸酐酶结合,也与血浆中的白蛋白、α2-巨球蛋白和氨基酸结合。白蛋白和氨基酸结合的锌可以扩散穿过组织膜。锌通过尿液和粪便排出体外。摄入一定量的硝酸盐和亚硝酸盐是人类氮循环的正常部分。在适当的条件下,硝酸盐可以在胃肠系统中转化为亚硝酸盐,显著增加硝酸盐的毒性效力。硝酸盐的主要代谢途径是转化为亚硝酸盐,然后转化为氨。亚硝酸盐、硝酸盐及其代谢物通过尿液排出体外。
Zinc can enter the body through the lungs, skin, and gastrointestinal tract. Intestinal absorption of zinc is controlled by zinc carrier protein CRIP. Zinc also binds to metallothioneins, which help prevent absorption of excess zinc. Zinc is widely distributed and found in all tissues and tissues fluids, concentrating in the liver, gastrointestinal tract, kidney, skin, lung, brain, heart, and pancreas. In the bloodstream zinc is found bound to carbonic anhydrase in erythrocytes, as well as bound to albumin, _2-macroglobulin, and amino acids in the the plasma. Albumin and amino acid bound zinc can diffuse across tissue membranes. Zinc is excreted in the urine and faeces. Intake of some amount of nitrates and nitrites is a normal part of the nitrogen cycle in humans. In vivo conversion of nitrates to nitrites can occur in the gastrointestional tract under the right conditions, significantly enhancing nitrates' toxic potency. The major metabolic pathway for nitrate is conversion to nitrite, and then to ammonia. Nitrites, nitrates, and their metabolites are excreted in the urine. (L1137, L49)
来源:Toxin and Toxin Target Database (T3DB)