Bremner I, Mills C F
Philos Trans R Soc Lond B Biol Sci. 1981 Aug 14;294(1071):75-89. doi: 10.1098/rstb.1981.0090.
Intestinal absorption of many essential trace elements probably occurs by saturable and carrier-mediated processes. The nature and efficiency of these are influenced by a range of physiological, nutritional and genetic variables. Special emphasis is given to the influence of exogenous and endogenous ligands of small molecular mass in the intestinal lumen on absorptive efficiency. The effect of enterocyte proteins such as metallothionein which, by sequestering metals, influence their fate during absorption is also considered. Changes in the metabolic activity of the intestinal mucosa induced by copper or zinc deficiencies influence the fate of other nutrients, either by inhibiting intracellular transport or by preventing the degradation of potential antagonists of absorption. Conflicting evidence of roles for plasma albumin, transferrin and caeruloplasmin in the transport of zinc and copper is considered. The extent, location and form in which trace elements are stored in tissues differs between elements and between species. Retention and utilization are also influenced by pregnancy, lactation, stage of foetal development and by genetic variables. Better definition of the effects of these variables would improve the validity of estimates of the trace element requirements of man and other animals.
许多必需微量元素的肠道吸收可能通过可饱和的载体介导过程进行。这些过程的性质和效率受一系列生理、营养和遗传变量的影响。特别强调肠腔内小分子质量的外源性和内源性配体对吸收效率的影响。还考虑了肠细胞蛋白（如金属硫蛋白）的作用，金属硫蛋白通过螯合金属影响其在吸收过程中的命运。铜或锌缺乏引起的肠黏膜代谢活性变化，通过抑制细胞内转运或阻止吸收潜在拮抗剂的降解，影响其他营养素的命运。文中讨论了血浆白蛋白、转铁蛋白和铜蓝蛋白在锌和铜转运中作用的相互矛盾的证据。微量元素在组织中的储存程度、位置和形式因元素和物种而异。妊娠、哺乳、胎儿发育阶段和遗传变量也会影响微量元素的保留和利用。更好地界定这些变量的影响将提高对人类和其他动物微量元素需求估计的准确性。
