Díaz F, Blázquez E
Departamento de Fisiología, Universidad de Oviedo, Spain.
Rev Esp Fisiol. 1987 Sep;43(3):303-10.
The appearance and fluctuations of specific insulin binding sites in several tissues in vivo during rat development, have been determined. After intravenous administration of 125I-insulin to fetal, suckling and adult rats, changes on specific hormone uptake were observed depending on the tissues tested and on the age of animals. Thus, in liver, specific insulin uptake was much greater in 19 day-old fetuses and 10 day-old suckling animals than in adult rats. By contrast, brown fat and spleen insulin uptake was undetected in fetal animals but present in suckling rats, while lung insulin uptake was absent in the adults but present in fetal and suckling animals. Of interest were the specific insulin uptakes by three different muscle tissues. In fact, heart insulin uptake was much higher in younger animals than in adult rats, while in the diaphragm it was significantly smaller in all groups and in skeletal muscles hormone uptake was much smaller than in the other two muscle tissues and was even absent in the fetuses. In those tissues that had previously been shown to exhibit a specific insulin uptake, the iodinated hormone uptake decreased proportionally with simultaneous injection of increasing amounts of unlabelled insulin. These results indicate that insulin binding sites appear at different times and fluctuate in a different manner according to the tissues tested during rat development; this might be important in the stimulation of the functional activities of those tissues during perinatal age.
已确定了大鼠发育过程中体内几种组织中特定胰岛素结合位点的出现和波动情况。给胎儿、哺乳期和成年大鼠静脉注射¹²⁵I-胰岛素后，根据所测试的组织和动物年龄，观察到特定激素摄取的变化。因此，在肝脏中，19日龄胎儿和10日龄哺乳期动物的特定胰岛素摄取量比成年大鼠大得多。相比之下，胎儿动物未检测到棕色脂肪和脾脏的胰岛素摄取，但哺乳期大鼠存在这种摄取，而成年动物的肺胰岛素摄取不存在，但胎儿和哺乳期动物存在。有趣的是三种不同肌肉组织的特定胰岛素摄取情况。事实上，年轻动物的心脏胰岛素摄取量比成年大鼠高得多，而在膈肌中，所有组的摄取量都显著较小，在骨骼肌中，激素摄取量比其他两种肌肉组织小得多，甚至在胎儿中不存在。在先前已显示出特定胰岛素摄取的那些组织中，随着同时注射越来越多的未标记胰岛素，碘化激素摄取量成比例下降。这些结果表明，胰岛素结合位点在大鼠发育过程中根据所测试的组织在不同时间出现并以不同方式波动；这在围产期刺激这些组织的功能活动中可能很重要。
