Leong Weng-In, Bowlus Christopher L, Tallkvist Jonas, Lönnerdal Bo
Department of Nutrition, University of California, Davis, California 95616, USA.
Am J Physiol Gastrointest Liver Physiol. 2003 Dec;285(6):G1153-61. doi: 10.1152/ajpgi.00107.2003. Epub 2003 Sep 4.
Two iron transporters, divalent metal transporter1 (DMT1) and ferroportin1 (FPN1) have been identified; however, their role during infancy is unknown. We investigated DMT1, FPN1, ferritin, and transferrin receptor expression, iron absorption and tissue iron in iron-deficient rat pups, iron-deficient rat pups given iron supplements, and controls during early (day 10) and late infancy (day 20). With iron deficiency, DMT1 was unchanged and FPN1 was decreased (-80%) at day 10. Body iron uptake, mucosal iron retention, and total iron absorption were unchanged. At day 20, DMT1 increased fourfold and FPN1 increased eightfold in the low-Fe group compared with controls. Body iron uptake and total iron absorption were increased, and mucosal iron retention was decreased with iron deficiency. Iron supplementation normalized expression levels of the transporters, body iron uptake, mucosal iron retention, and total iron absorption of the low-Fe group to those of controls at day 20. In summary, the molecular mechanisms regulating iron absorption during early infancy differ from late infancy when they are similar to adult animals, indicating developmental regulation of iron absorption.
现已鉴定出两种铁转运蛋白，即二价金属转运蛋白1（DMT1）和铁转运蛋白1（FPN1）；然而，它们在婴儿期所起的作用尚不清楚。我们研究了缺铁幼鼠、补充铁剂的缺铁幼鼠以及早期（第10天）和晚期婴儿期（第20天）的对照鼠中DMT1、FPN1、铁蛋白和转铁蛋白受体的表达、铁吸收及组织铁含量。缺铁时，第10天DMT1无变化，FPN1降低（-80%）。机体铁摄取、黏膜铁潴留及总铁吸收均无变化。第20天，与对照组相比，低铁组DMT1增加四倍，FPN1增加八倍。缺铁时机体铁摄取和总铁吸收增加，黏膜铁潴留减少。在第20天，铁补充使低铁组转运蛋白的表达水平、机体铁摄取、黏膜铁潴留及总铁吸收恢复至对照组水平。总之，婴儿早期调节铁吸收的分子机制与晚期不同，晚期与成年动物相似，表明铁吸收存在发育调控。
