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Localization of angiotensinogen and its mRNA in hepatocytes of adult and embryonic rats.

血管紧张素原及其 mRNA 在成年和胚胎大鼠肝细胞中的定位。

基本信息

批准号：
62570003
负责人：
UCHIYAMA Yasuo
金额：
$ 1.15万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

To examine localization of angiotensinogen (ANG) and its mRNA in hepatocytes of adult and embryonic rats, in situ hybridization and immunocytochemistry were applied to liver tissue. In in situ hybridization used, specific as well as non-specific signals appeared in liver tissue, so that the present study was performed mainly using immunocytochemistry. For this, we purified ANG from nephrectomized rat plasma, and prepared anti-ANG, whose specificity was confirmed by immunoblotting, radioimmunoassay and immunocytochemistry. By immunocytochemistry, a clear-cut variation in immunoreactivity for ANG was detected in adult rat hepatocytes over 24 h; it was strong early in the light period, whereas it was weak early in the dark period. The drastic variation in the reactivity was seen especially in periportal hepatocytes. The change in immunoreactivity for ANG in hepatocytes over 24 h is similar to that in quantity of the rough endoplasmic reticulum in hepatocytes (Uchiyama and Asari 1984); ANG content in hepatocytes is high, when proteim synthesis of hepatocytes is active. As for pre- and postnatal development, ANG appeared faintly in hepatocytes at 17 days of gestation, while at 20 days, immunoreactivity for ANG became vivid. At birth, the strongest immunoreactivity was detected in hepatocytes, while the reactivity in hepatocytes after 5 postnatal days became similar to that of adult hepatocytes. The result that ANG content in hepatocytes increases from 17 to 20 days of gestation is similar to that of renin content in juxtaglomerular cells. This indicates that ANG as the renin substrate participates in the renin-angiotensin system at the end of fetal life, which regulates blood pressure.

采用原位杂交和免疫细胞化学方法，观察血管紧张素原（ANG）及其mRNA在成年和胚胎大鼠肝细胞中的定位。在原位杂交中，肝脏组织中出现特异性和非特异性信号，因此本研究主要使用免疫细胞化学进行。为此，我们从肾切除大鼠血浆中纯化ANG，制备抗ANG，通过免疫印迹、放射免疫测定和免疫细胞化学证实其特异性。通过免疫细胞化学，在24小时内检测到成年大鼠肝细胞中ANG的免疫反应性明显变化；它在光明期早期较强，而在黑暗期早期较弱。反应性的剧烈变化在门静脉周围肝细胞中尤为明显。肝细胞对ANG的免疫反应性在24小时内的变化与肝细胞粗内质网数量的变化相似（Uchiyama和Asari 1984）；肝细胞内ANG含量高，肝细胞蛋白质合成活跃。在产前和产后发育方面，妊娠第17天肝细胞中出现少量ANG，妊娠第20天肝细胞对ANG的免疫反应明显。出生时，肝细胞的免疫反应性最强，出生5天后，肝细胞的免疫反应性与成人肝细胞相似。妊娠17 ~ 20 d肝细胞ANG含量升高的结果与肾小球旁细胞肾素含量升高的结果相似。这表明ANG作为肾素底物参与胎儿生命末期肾素-血管紧张素系统调节血压。