摘要
应用放射配体结合法，以２－［（１２５）Ｉ］降黑素为配体证实了中枢性免疫器官──鸡腔上囊存在降黑素特异结合位点。该结合位点可以满足特异结合位点的全部条件：低结合容量，高亲和力，可逆性和可饱和性，对降黑素（Ｍ）高度特异性。昼夜节律研究表明Ｍ存在昼夜节律。亚细胞分布的研究揭示结合位点以细胞核含量最高，同时发现具年龄依赖的降低。本研究表明腔上囊是Ｍ作用的靶器官，提示Ｍ对免疫系统的调节是直接作用的结果。
Melatonin binding sites in the membrane preparations of the bursa of Fabricius of chicken were studied with 2-[125I] iodomelatonin (125I]M), as a radioligand. The binding sites were stable,saturable, reversible and of high affinity. Scatchard analysis revealed an equilibrium binding constant (Kd) of 49. 5±6. 1pmol/L with a total number of binding sites (Bmax) of 1. 18±0. 05 fmol/mg of protein. Studies on circadian rhythm showed that Bmax was 59. 6 percent higher at mid-light (ML) than at mid-dark (MD). Specificity studies indicated that the binding sites were highly specific for melatonin. There was an age-related decrease in [125I]M binding sites of bursal membranes with higher densities in the neonate. Our studies demonstrate the presence of specific binding sites for [125I]M in the bursa of Fabricius of chickens,which is a target organ of melatonin and thus melatonin exerts a direct effect on the immune system.
出处
《标记免疫分析与临床》
CAS
1995年第1期18-21,共4页
Labeled Immunoassays and Clinical Medicine
关键词
降黑素
免疫器官
放射配体测定
腔上囊
Melatonin
Binding sites/melatonin
Radioligand assay
Bursa of Fabricius
