Lew J Y, Zawadzka H, Feigenblum D, Tang D, Filer D, Benedetto P, Goldstein M
Department of Psychiatry, New York University Medical Center, NY 10016.
Eur J Pharmacol. 1990 Jun 12;188(6):329-34. doi: 10.1016/0922-4106(90)90193-2.
The regulation and molecular properties of the dopamine (DA) D2 receptors were compared in the prolactin-secreting 7315a anterior pituitary tumor with those in the striatum of rats. Chronic treatment with haloperidol increases the maximal binding for [3H]spiroperidol in tumor and striatum, but the percent increase is much higher in tumor than in striatum. Photoaffinity labelling of DA D2 receptors with N-(p-azido-m-[125I]iodophenethyl)spiperone ([125I]N3-NAPS) yielded a major specifically labeled peptide with the Mr of 32-34 kDa in tumor, and two specifically labeled peptides with Mr of 32-34 and 92-94 kDa in striatum. The analysis of DA D2 receptor mRNA shows that the size is similar in tumor and striatum. The DA D2 receptor mRNA in tumor is very low and chronic treatment with haloperidol produces a considerable increase of the specific mRNA. It is postulated that the reported defect in regulation of prolactin release by DA agonists might be due to posttranslational changes in the tumor DA D2 receptor.
在分泌催乳素的7315a垂体前叶肿瘤中，对多巴胺（DA）D2受体的调节和分子特性与大鼠纹状体中的进行了比较。用氟哌啶醇长期治疗可增加肿瘤和纹状体中[3H]螺哌啶的最大结合，但肿瘤中的增加百分比远高于纹状体。用N-（对叠氮基间-[125I]碘苯乙基）螺哌酮（[125I]N3-NAPS）对DA D2受体进行光亲和标记，在肿瘤中产生一条主要的特异性标记肽，其分子量为32 - 34 kDa，在纹状体中产生两条特异性标记肽，分子量分别为32 - 34 kDa和92 - 94 kDa。对DA D2受体mRNA的分析表明，其大小在肿瘤和纹状体中相似。肿瘤中的DA D2受体mRNA非常低，用氟哌啶醇长期治疗可使特异性mRNA显著增加。据推测，报道的DA激动剂对催乳素释放调节的缺陷可能是由于肿瘤DA D2受体的翻译后变化所致。
