Di Carlo R, Muccioli G, Papotti M, Bussolati G
Department of Experimental Pharmacology, University of Naples Federico II, Italy.
Brain Res. 1992 Jan 20;570(1-2):341-6. doi: 10.1016/0006-8993(92)90599-5.
We have studied the binding of 125I-labeled human prolactin (PRL) to membranes from various regions of the human brain (hypothalamus, cerebral cortex, cerebellum and choroid plexus) derived from autopsy specimens. Among the various regions studied, the choroid plexus of both male and female subjects showed the highest specific binding and a clearly detectable specific binding was also observed in the hypothalamus of both sexes, whereas it was very low in other brain regions. No significant sex differences in PRL binding to various brain regions were observed except for the hypothalamus where a higher binding was seen in female subjects. The binding did not vary with the age of the subjects. Moreover, the cause of death and the time elapsed from death to autopsy in this study did not affect the binding significantly. The binding of 125I-labeled human PRL to hypothalamus and choroid plexus membranes from female specimens was inhibited in a dose-dependent manner by both unlabeled human and ovine PRL and by human growth hormone (GH), but not by other polypeptide hormones. Scatchard analysis of the binding revealed the presence of saturable binding sites with low capacity and high affinity for human PRL ligand. These results provide strong preliminary evidence for the presence of PRL binding sites in the human brain.
我们研究了125I标记的人催乳素（PRL）与来自尸检标本的人脑不同区域（下丘脑、大脑皮层、小脑和脉络丛）的膜的结合情况。在所研究的不同区域中，男性和女性受试者的脉络丛均显示出最高的特异性结合，并且在两性的下丘脑中也观察到明显可检测到的特异性结合，而在其他脑区则非常低。除下丘脑外，未观察到PRL与不同脑区结合的显著性别差异，在下丘脑中女性受试者的结合较高。结合情况不随受试者年龄而变化。此外，本研究中的死因以及从死亡到尸检的时间间隔对结合情况没有显著影响。未标记的人PRL、羊PRL和人生长激素（GH）均以剂量依赖性方式抑制125I标记的人PRL与女性标本下丘脑和脉络丛膜的结合，但其他多肽激素则无此作用。对结合情况的Scatchard分析表明存在对人PRL配体具有低容量和高亲和力的可饱和结合位点。这些结果为人类大脑中存在PRL结合位点提供了有力的初步证据。
