Matsuno A, Katakami H, Nagashima T, Teramoto A, Osamura R Y, Kirino T
Department of Neurosurgery, Teikyo University Ichihara Hospital, Ichihara City, Chiba, Japan.
Hum Pathol. 2000 Jul;31(7):789-94. doi: 10.1053/hupa.2000.8450.
Growth hormone-releasing hormone (GHRH) is a well-known hypothalamic hormone that stimulates the synthesis and release of growth hormone (GH) as well as the proliferation of GH-producing cells in the anterior pituitary gland. Recent reports have shown GHRH synthesis in pituitary somatotroph adenomas, but GHRH immunoreactivity has not been shown in previous studies. To confirm the role of locally generated GHRH for the progression of somatotroph adenomas, we investigated the expression of GHRH in 25 pituitary somatotroph adenomas immunohistochemically, through the use of both conventional avidin-biotin-complex (ABC) method and novel catalyzed signal amplified (CSA) system. In addition, we investigated the expression of GHRH mRNA and GHRH receptor mRNA with in situ hybridization (ISH) using the CSA system. The weak immunopositivity of GHRH was observed in only 2 adenomas (8.0%) of 25 somatotroph adenomas using the ABC method. In contrast, 15 adenomas (60.0%) of 25 somatotroph adenomas were immunopositive for GHRH, as shown by CSA system. Very few of nonsomatotroph adenomas were immunopositive for GHRH using the CSA system. The expression of GHRH mRNA was confirmed, using the CSA-ISH system in 13 adenomas (72.2%) of 18 somatotroph adenomas. In 11 adenomas (61.1%) of 18 somatotrophic adenomas, the expression of GHRH receptor mRNA was demonstrated using the CSA-ISH system. This is a first report that clarified histopathologically GHRH production in pituitary somatotrophic adenomas. The demonstration of GHRH and its receptor expression is meaningful in clarifying the autocrine or paracrine regulation of GHRH in GH production and progression of pituitary somatotroph adenomas.
生长激素释放激素（GHRH）是一种著名的下丘脑激素，它能刺激生长激素（GH）的合成与释放，以及垂体前叶中产生GH的细胞的增殖。最近的报告显示垂体生长激素腺瘤中有GHRH合成，但先前的研究未显示GHRH免疫反应性。为了证实局部产生的GHRH在生长激素腺瘤进展中的作用，我们通过使用传统的抗生物素蛋白-生物素复合物（ABC）法和新型催化信号放大（CSA）系统，对25例垂体生长激素腺瘤进行了GHRH免疫组织化学表达研究。此外，我们使用CSA系统通过原位杂交（ISH）研究了GHRH mRNA和GHRH受体mRNA的表达。使用ABC法时，在25例生长激素腺瘤中仅2例腺瘤（8.0%）观察到GHRH弱阳性。相比之下，如CSA系统所示，25例生长激素腺瘤中有15例腺瘤（60.0%）对GHRH呈免疫阳性。使用CSA系统时，很少有非生长激素腺瘤对GHRH呈免疫阳性。使用CSA-ISH系统在18例生长激素腺瘤中的13例腺瘤（72.2%）中证实了GHRH mRNA的表达。使用CSA-ISH系统在18例生长激素腺瘤中的11例腺瘤（61.1%）中证实了GHRH受体mRNA的表达。这是第一份从组织病理学上阐明垂体生长激素腺瘤中GHRH产生的报告。GHRH及其受体表达的证实对于阐明GHRH在垂体生长激素腺瘤的GH产生和进展中的自分泌或旁分泌调节具有重要意义。
