Tissue distribution of growth hormone releasing hormone receptor

人生长激素释放激素（GHRH）是调节生长激素分泌和生长激素细胞增殖所必需的。1992年，对人、大鼠和小鼠的GHRH受体（GHRH-R）进行了分子克隆。然而，GHRH-R在人垂体腺瘤中的表达仅通过逆转录酶-PCR（RT-PCR）和北方印迹分析进行了有限程度的研究。这种表达在人类垂体腺瘤和非肿瘤垂体组织显然还没有检查原位杂交组织化学（ISH）。本研究采用RT-PCR和原位杂交技术，对人GHRH-R mRNA在非肿瘤性垂体组织和垂体腺瘤中的表达进行了研究。在所有非肿瘤垂体标本中，这种表达被RT-PCR所识别。只有GH细胞表达GHRH-R mRNA，如一个年轻女孩的垂体原位杂交所示。在38例垂体腺瘤中，GHRH-R mRNA仅在GH腺瘤中有强信号，而在正常垂体催乳素细胞、催乳素腺瘤细胞及其它类型腺瘤细胞中均未见明显表达。GH产生细胞的肿瘤发生或肿瘤生长可能与GHRH-R mRNA的强表达有关。

The human growth hormone-releasing hormone (GHRH) is essential to the regulation of GH secretion and somatotroph proliferation. In 1992, molecular clonings of GHRH-receptor (GHRH-R) of human, rat and mouse were conducted. However, the expression of GHRH-R in human pituitary adenomas has been studied to only a limited extent by reverse-transcriptase-PCR (RT-PCR) and Northern blot analysis. This expression in human pituitary adenomas and non-neoplastic pituitary tissue apparently has not been examined by in situ hybridization histochemistry (ISH). The expression of human GHRH-R mRNA by RT-PCR and ISH was studied here not only in non-neoplastic pituitary tissue but pituitary adenomas as well. In all non-neoplastic pituitary specimens, this expression was recognized by RT-PCR.Only GH cells expressed GHRH-R mRNA,as indicated by in situ hybridization in the pituitary gland from a young girl. Among 38 pituitary adenomas, strong signals for GHRH-R mRNA were observed only in GH producing adenomas by RT-PCR and ISH.It is significant that no appreciable expression of GHRH-R was seen in the prolactin cells of normal pituitary gland, prolactinoma cells or cells from other types of adenomas.Based on the above, tumorigenesis or tumor growth of GH-producing cells would appear possibly related to the strong expression of GHRH-R mRNA.