摘要
用12 5I标记结合分子排阻高效液相色谱 (SHPLC)研究小鼠体内重组人血小板生成素(rhTPO)代谢、分布和排泄。标记 rhTPO体外可刺激TPO依赖细胞系TD3增殖 ;体内刺激外周血血小板增加活性与未标记标准rhTPO相似 ,而SHPLC放化纯度 (96 .9± 1.5 ) %(n =3)符合药动学研究要求。小鼠皮下注射 1微克 鼠后血清和尿SHPLC分析除原形外 ,出现了分子量较小的12 5I 代谢物Ⅰ和Ⅱ。血清以原形和12 5I 代谢物Ⅰ为主 ,尿中有少量原形 ,主要是12 5I 代谢物Ⅰ和Ⅱ。原形消除半衰期为 10 .8小时 ,组织TCA可沉淀放射性分布特点是 :靶器官骨髓较高 ,泌尿系统最高 ,脑内最低。主要经尿排泄 ,少量经粪排泄。 72小时排出 (98.3± 5 .6 ) %。
The metabolism, distribution and excretion profiles of recombinant human thrombopoietin (rhTPO) in mice were studied by means of 125I-labeled rhTPO ( 125I-rhTPO) combined with size exclusive high performance liquid chromatography (SHPLC) or trichloroacetic acid (TCA) precipitation analysis. 125I-rhTPO was prepared by iodogen method. Purification was performed on Sephacryl S-200 HR gel. Radioactive-purity of 125I-rhTPO identified by SHPLC was (96.9±1.5)%(n=3). The proliferation effect of TPO dependent cell line (TD-3) and the increase of peripheral platelet counts in mouse by 125I-rhTPO demonstrated that 125I-labeled protein maintained the biological activities of TPO both in vitro and in vivo. SHPLC analysis of serum and urine samples taken after sc 1 μg/mouse (345 kBq/mouse) of 125I-rhTPO revealed that there were two lower molecular weight 125I-degradation metabolites ( 125I-MⅠ and 125I-MⅡ) other than parent molecule. 125I-MⅠ was mainly found in urine, and 125I-MⅡ was detected both in serum and in urine. The maximal concentration of 125I-rhTPO was reached at 2 hours after injection. The terminal half-life was 10.8 hours, which was much longer than those of other peptides. TCA precipitable radioactivity in tissue showed that the radioactivity in bone marrow was rather high. The highest level was found in urinary system. Levels in adrenals, lymph nodes, and fat were near to that in serum. Lowest was found in brain. The main excretion route was urinary system and (98±5.6)% of 125I-rhTPO was excreted within 72 hours after dosing.
出处
《中国实验血液学杂志》
CAS
CSCD
2001年第4期318-322,共5页
Journal of Experimental Hematology
基金
国家自然科学基金重点资助项目 编号39930 180~~
