Tyson L M, Browne C A, Jenkin G, Thorburn G D
Department of Physiology, Monash University, Clayton, Victoria, Australia.
J Endocrinol. 1989 Oct;123(1):121-30. doi: 10.1677/joe.0.1230121.
125I-Labelled murine epidermal growth factor (EGF) was injected or infused into conscious ewes through the jugular vein. Its disappearance from the circulation and the pattern of its distribution in other body tissues and compartments were observed. Single bolus injections of 125I-labelled EGF resulted in a transient peak of radioactive EGF in the circulation which occurred within 1 min of the injection. This was followed by a very rapid fall in radioactivity in the plasma (t1/2 approximately 1 min) and the gradual appearance of 125I-labelled EGF in the urine. Immunoprecipitable 125I-labelled EGF could be detected in urine within 5 min of the start of the experiment. 125I-Labelled EGF accumulated in the urine for several hours following the injection, although with increasing time a substantial amount of non-immunoprecipitable iodide was also found. The rate of disappearance of the 125I-labelled EGF from the plasma of the ewe was found to be faster than the rate of disappearance of free [125I]iodide that had been injected into the ewe. 125I-Labelled EGF was also administered by a continuous infusion following an initial bolus injection. This again resulted in a rapid initial fall in radioactivity in blood, followed by a slow rise throughout the period of the infusion. When the infusion was stopped, there was a 15-min period of rapid readjustment, after which the radioactivity in the blood fell at a much slower rate (t1/2 approximately 70 min) than was seen initially. Again, intact 125I-labelled EGF was transferred to urine throughout the experiment. At autopsy, 125I-labelled EGF was increased in bile, liver, thyroid and kidney. Although most of the 125I found in the thyroid was free iodide, some EGF-like material was also present. There was also EGF-like material found in both the kidney cortex and the kidney medulla. These results indicate that complex multi-compartment pathways for the uptake, distribution and clearance of 125I-labelled EGF exist in the sheep.
将125I标记的小鼠表皮生长因子（EGF）通过颈静脉注射或输注到清醒的母羊体内。观察其在循环中的消失情况以及在身体其他组织和腔室中的分布模式。单次推注125I标记的EGF会导致循环中放射性EGF出现短暂峰值，该峰值在注射后1分钟内出现。随后血浆中的放射性迅速下降（半衰期约为1分钟），并且125I标记的EGF逐渐出现在尿液中。在实验开始后5分钟内即可在尿液中检测到免疫沉淀的125I标记的EGF。注射后，125I标记的EGF在尿液中积累了数小时，尽管随着时间的推移，也发现了大量不可免疫沉淀的碘化物。发现125I标记的EGF从母羊血浆中消失的速率比注入母羊体内的游离[125I]碘化物的消失速率更快。在初始推注后，也通过持续输注给予125I标记的EGF。这再次导致血液中放射性迅速初始下降，随后在整个输注期间缓慢上升。当输注停止时，有一个15分钟的快速重新调整期，之后血液中的放射性下降速率比最初观察到的要慢得多（半衰期约为70分钟）。同样，在整个实验过程中，完整的125I标记的EGF都转移到了尿液中。尸检时，胆汁、肝脏、甲状腺和肾脏中的125I标记的EGF增加。尽管在甲状腺中发现的大部分125I是游离碘化物，但也存在一些EGF样物质。在肾皮质和肾髓质中也发现了EGF样物质。这些结果表明，绵羊体内存在125I标记的EGF摄取、分布和清除的复杂多腔室途径。
