Karle H, Hansen N E, Malmquist J, Karle A K, Larsson I
Scand J Haematol. 1979 Oct;23(4):303-12. doi: 10.1111/j.1600-0609.1979.tb02865.x.
Lactoferrin turnover was studied in the rabbit with 125I- and 131I-labelled human lactoferrin. Plasma lactoferrin activity showed a rapid decrease during the first 24 h, followed by a 'final slope' with a T1/2 of about 25 h. Turnover studies after transfer of plasma from one rabbit (A) 3 h after injection to another rabbit (B), showed a recovery of 100% compared to 30% in A rabbits but otherwise a similar disappearance curve. The rapid turnover was confirmed in whole body studies. Concomitantly with the initial dissapearance from the plasma, there was a marked accumulation of proteinbound activity only in the liver in both A and B rabbits. From these results, the rate of synthesis in normal man can be estimated at around 25 mg per d. The disappearance pattern and hepatic uptake are discussed in relation to knowledge about lactoferrin receptors in macrophages, asialo elimination, and fucose group recognition. Concerning the significance of lactoferrin turnover for iron metabolism it is concluded that the plasma turnover results are insufficient to explain the disturbance in iron kinetics seen in the anaemia of chronic disorders; however, it is likely that lactoferrin plays a role in iron metabolism within the extravascular space.
用125I和131I标记的人乳铁蛋白研究了家兔体内乳铁蛋白的周转率。血浆乳铁蛋白活性在最初24小时内迅速下降，随后是“终末斜率”，半衰期约为25小时。将注射后3小时的一只家兔（A）的血浆转移到另一只家兔（B）后进行的周转率研究表明，与A家兔的30%相比，回收率为100%，但消失曲线相似。全身研究证实了快速周转率。与血浆中最初的消失同时，A和B家兔的肝脏中仅出现了蛋白结合活性的明显积累。根据这些结果，估计正常人的合成速率约为每日25毫克。结合关于巨噬细胞中乳铁蛋白受体、去唾液酸消除和岩藻糖基团识别的知识，讨论了消失模式和肝脏摄取情况。关于乳铁蛋白周转率对铁代谢的意义，得出的结论是，血浆周转率结果不足以解释慢性疾病贫血中铁动力学的紊乱；然而，乳铁蛋白可能在血管外空间的铁代谢中起作用。
