Less than 80% of absorbed iron is promptly incorporated into erythrocytes of infants.
Less than 80% of absorbed iron is promptly incorporated into erythrocytes of infants.
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DOI：
10.1093/jn/130.1.45
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
S. J. Fomon;E. Ziegler;R. E. Serfass;S. Nelson;R. Rogers;J. A. Frantz
中科院分区：
文献类型：
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作者：
S. J. Fomon;E. Ziegler;R. E. Serfass;S. Nelson;R. Rogers;J. A. Frantz
红细胞掺入给药的铁同位素已被用作铁保留的替代品，假设（在正常和缺铁成人中得到验证）80-100%的保留同位素迅速掺入循环红细胞。这一假设在婴儿或儿童中尚未得到证实。本研究的目的是同时测定正常婴儿对稳定同位素（58）Fe的吸收和红细胞掺入。在一项初步研究（研究1）中，我们证明摄入的同位素的粪便排泄主要发生在给药后的前4天内，但持续到摄入后7天之后，也就是说，超过了粪便中的同位素可以通过未能进入肠细胞的同位素排泄来解释的点。或通过富含同位素的肠细胞的脱落来解释。在研究2中，我们给9名年龄较小（20-69 d）和9名年龄较大（165-215 d）的足月婴儿服用（58）Fe，并收集11 d的粪便。~（58）Fe的几何平均存留率，年龄较小的婴儿为31.2%，第11天为26.9%，年龄较大的婴儿为35.0%，第11天为32.5%。摄入后14 d，（58）Fe的红细胞掺入量为5.2%的剂量，由年龄较小的婴儿和12.5%的年龄较大的婴儿。因此，保留（11天）同位素的利用率为19.8%，由年龄较小的婴儿和38.3%的年龄较大的婴儿。我们的结论是，远低于80%的保留同位素迅速纳入红细胞（利用）的婴儿。
Erythrocyte incorporation of an administered iron isotope has been used as a surrogate for iron retention on the assumption (validated in normal and iron-deficient adults) that 80-100% of the retained isotope is promptly incorporated into circulating erythrocytes. This assumption has not been validated in infants or children. The purpose of our study was to determine concurrently in normal infants absorption and erythrocyte incorporation of the stable isotope, (58)Fe. In a preliminary study (Study 1), we demonstrated that fecal excretion of ingested isotope occurs predominantly during the first 4 d after administration but continues beyond 7 d after ingestion, that is, beyond the point at which isotope in feces can be explained either by excretion of isotope that failed to enter enterocytes or by exfoliation of isotope-enriched enterocytes. In Study 2, we administered (58)Fe to nine younger (age 20-69 d) and nine older (age 165-215 d) term infants and collected feces for 11 d. Geometric mean retention of (58)Fe by the younger infants was 31.2% of intake at 4 d and 26.9% at 11 d, and by the older infants, 35.0% at 4 d and 32.5% at 11 d. Erythrocyte incorporation of (58)Fe 14 d after ingestion was 5.2% of the dose by the younger infants and 12.5% by the older infants. Utilization of retained (11 d) isotope thus was 19.8% by the younger infants and 38.3% by the older infants. We conclude that far less than 80% of retained isotope is promptly incorporated into erythrocytes (utilized) by infants.