Lloyd R V, Anagnostou D, Chandler W F
Department of Pathology, University of Michigan Medical Center, Ann Arbor.
Mod Pathol. 1988 Jan;1(1):51-6.
Dopamine receptors were analyzed in plasma membranes from five null cell adenomas and five normal human pituitary tissues by [3H]spiperone binding. One prolactin (PRL)-producing, one growth hormone (GH)-producing, and an adrenocorticotropic (ACTH)-producing adenoma were also analyzed for dopamine receptors. Immunohistochemical staining showed that all null cell adenomas were positive for chromogranin A, while 20 to 30% of cells in each normal pituitary stained for this marker. The dissociation constant (Kd) and maximal binding capacity (Bmax) were 1.07 +/- 0.49 nM and 148 +/- 34 fmol/mg protein for null cell adenomas and 1.23 +/- 0.20 nM and 107 +/- 21 fmol/mg protein for normal pituitary tissues. The one PRL adenoma had a similar Kd but had a 5.6-fold higher Bmax than the mean Bmax for the null cell adenomas. These results indicate that immunohistochemically characterized null cell adenomas as well as normal pituitaries express dopamine receptors, but that the binding sites in null cell adenomas are much less those in PRL-secreting adenomas.
通过[3H]螺哌隆结合法对来自5例无功能细胞腺瘤和5例正常人体垂体组织的质膜中的多巴胺受体进行了分析。还对1例分泌催乳素（PRL）的腺瘤、1例分泌生长激素（GH）的腺瘤和1例分泌促肾上腺皮质激素（ACTH）的腺瘤进行了多巴胺受体分析。免疫组织化学染色显示，所有无功能细胞腺瘤嗜铬粒蛋白A均呈阳性，而每个正常垂体中有20%至30%的细胞对此标志物染色。无功能细胞腺瘤的解离常数（Kd）和最大结合容量（Bmax）分别为1.07±0.49 nM和148±34 fmol/mg蛋白，正常垂体组织的解离常数和最大结合容量分别为1.23±0.20 nM和107±21 fmol/mg蛋白。1例PRL腺瘤的Kd与之相似，但Bmax比无功能细胞腺瘤的平均Bmax高5.6倍。这些结果表明，经免疫组织化学鉴定的无功能细胞腺瘤以及正常垂体均表达多巴胺受体，但无功能细胞腺瘤中的结合位点比分泌PRL的腺瘤中的结合位点少得多。
