促甲状腺激素释放激素（TRH）对大鼠胰腺基因表达的影响：通过微阵列杂交进行研究

Yano Naohiro, Luo LuGuang

Hallett Center for Diabetes and Endocrinology, Rhode Island Hospital, Brown Medical School, Providence, RI 02903, USA.

JOP. 2004 Jul;5(4):193-204.

CONTEXT

Thyrotropin releasing hormone (TRH), originally identified as a hypothalamic hormone, expresses in the pancreas. The effects of TRH such as, inhibiting amylase secretion in rats through a direct effect on acinar cells, enhancing basal glucagon secretion from isolated perfused rat pancreas, and potentiating glucose-stimulated insulin secretion in perfused rat islets and insulin-secreting clonal beta-cell lines, suggest that TRH may play a role in pancreas. TRH also enlarged pancreas and increased pancreatic DNA content but deletion of TRH gene expression caused hyperglycemia in mice, suggesting that TRH may play a critical role in pancreatic development; however, the biological mechanisms of TRH in the adult pancreas remains unclear.

OBJECTIVES

This study explored the effect of TRH on rat pancreas.

SUBJECTS

Four male-Sprague-Dawley-rats (200-250 g) were given 10 microg/kg BW of TRH intraperitoneally on 1st and 3rd day and sacrificed on 7th day. Four same-strain rats without TRH injection served as controls.

MAIN OUTCOME MEASURES

Wet pancreatic weights were measured. Pancreatic tissues were homogenized and extracted. The insulin levels of the extracts were measured by ELISA. Total RNA from the pancreases were fluorescently labeled and hybridized to microarray with 1,081 spot genes.

RESULTS

TRH increased pancreatic wet weight and insulin contents. About 75% of the 1,081 genes were detected in the pancreas. TRH regulated up 99 genes and down 76 genes. The administration of TRH induced various types of gene expressions, such as G-protein coupled receptors (GPCR) and signal transduction related genes (GPCR kinase 4, transducin beta subunit 5, arrestin beta1MAPK3, MAPK5, c-Src kinase, PKCs, PI3 kinase), growth factors (PDGF-B, IGF-2, IL-18, IGF-1, IL-2, IL-6, endothelin-1) and apoptotic factors (Bcl2, BAD, Bax).

CONCLUSION

Reprogramming of transcriptome may be a way for TRH-regulation of pancreatic cellular functions.

背景

促甲状腺激素释放激素（TRH）最初被鉴定为一种下丘脑激素，在胰腺中也有表达。TRH的作用，如通过对腺泡细胞的直接作用抑制大鼠淀粉酶分泌、增强离体灌注大鼠胰腺的基础胰高血糖素分泌，以及增强灌注大鼠胰岛和胰岛素分泌克隆β细胞系中的葡萄糖刺激的胰岛素分泌，提示TRH可能在胰腺中发挥作用。TRH还可使胰腺增大并增加胰腺DNA含量，但TRH基因表达缺失会导致小鼠出现高血糖，提示TRH可能在胰腺发育中起关键作用；然而，TRH在成年胰腺中的生物学机制仍不清楚。

目的

本研究探讨TRH对大鼠胰腺的影响。

对象

4只雄性Sprague-Dawley大鼠（200-250g）在第1天和第3天腹腔注射10μg/kg体重的TRH，并在第7天处死。4只未注射TRH的同品系大鼠作为对照。

主要观察指标

测量胰腺湿重。将胰腺组织匀浆并提取。通过酶联免疫吸附测定法测量提取物中的胰岛素水平。用荧光标记来自胰腺的总RNA，并与含有1081个斑点基因的微阵列杂交。

结果

TRH增加了胰腺湿重和胰岛素含量。在胰腺中检测到了1081个基因中的约75%。TRH上调了99个基因，下调了76个基因。TRH的给药诱导了各种类型的基因表达，如G蛋白偶联受体（GPCR）和信号转导相关基因（GPCR激酶4、转导蛋白β亚基5、抑制蛋白β1、丝裂原活化蛋白激酶3、丝裂原活化蛋白激酶5、c-Src激酶、蛋白激酶C、磷脂酰肌醇-3激酶）、生长因子（血小板衍生生长因子-B、胰岛素样生长因子-2、白细胞介素-18、胰岛素样生长因子-1、白细胞介素-2、白细胞介素-6、内皮素-1）和凋亡因子（Bcl2、BAD、Bax）。