垂体特异转录因子pit-1在垂体瘤中的表达及意义的实验研究

Study on expression and value of Pit-1 in pituitary adenomas

目的检测垂体特异转录因子pit-1在垂体腺瘤中的表达,研究Pit-1与激素水平、肿瘤侵袭性的关系,以探讨Pit-1在垂体瘤发病机制中的作用。方法根据术前激素水平、临床表现及术后病理诊断确定腺瘤类型,依影像学表现、术中所见及硬膜病检结果判断对肿瘤侵袭性分级,用免疫组化和RT-PCR分别测定Pit-1蛋白和pit-1mRNA的表达。结果Pit-1在GH腺瘤、PRL腺瘤、GH/PRL混合腺瘤中均有表达,与对照组相比,中、高度表达者占此3种腺瘤的78.8%(26/33),无功能腺瘤及ACTH腺瘤中无Pit-1蛋白的表达。pit-1mRNA在全部的GH腺瘤、PRL腺瘤、GH/PRL混合腺瘤和50%(5/10)的无功能腺瘤中有表达,在ACTH腺瘤组中无表达。GH、PRL、GH/PRL混合腺瘤组间pit-1mRNA的表达量差异无显著性,此3组均显著高于无功能腺瘤组(P<0.05)。GH、PRL腺瘤组中pit-1mRNA的表达量与其各自术前的激素水平呈显著正相关。在表达pit-1mRNA的腺瘤中,侵袭性组高于非侵袭性组。结论Pit-1的表达与垂体腺瘤的表型、功能有关,与某些激素(GH、PRL)水平、肿瘤的侵袭性呈正相关,在某些类型(GH、PRL、GH/PRL)的垂体瘤发病机制中起重要作用。

[Objective] To investigate the relationship between the pituitary-specific transefiption factor （Pit-1） expression level and biological behaviour in different types of human pituitary adenomas, and gain further insight about the value of Pit-1 on pathogenesis of pituitary adenomas. [Methods] According to serum hormone levels and clinical features and pathologic diagnosis, the type of pituitary adenomas was determined. The grades of pituitary adenomas invasiveness were depended on imaging and operation observation as well as the pathologic outcom of dura. Expression of Pit-1 protein was detected by immunohistochemical technique, and the expression of pit-1 mRNA was assayed by RT-PCR. [Results] Immunohistochemical studies revealed a high expression of Pit-1 protein in the nuclei of only three tumor types： GH, PRL and GH/PRL cell adenomas. Pit-1 mRNA was expressed in all GH, PRL, GH/PRL adenomas and in some non-functloning adenomas （5/10）. No Pit-1 mRNA expression was found in ACTH adenomas. Pit- 1 mRNA levels in GH, PRL, GH/PRL adenomas were similar and all higher than that in non-functioning adenomas （P 〈0.05）. Serum hormone （GH, PRL） level before operation was significantly related with Pit-1 mRNA level in GH, PRL adenoma （P 〈0.01）. The expression of Pit-1 in the group with invasiveness was higher than in the group with non-invasive -ness in all Pit-1 mRNA-positive adenomas. [Conclusion] The expression of Pit-1 is associated with adenomas phenotype and biological behaviour, so it has an important role in pathogenesis of cer-tain types pituitary adenomas.