Direct Evidence of Gonadotropin-Releasing Hormone (GnRH)-Stimulated Nitric Oxide Production in the LβT-2 Clonal Gonadotropes

被引：11

作者：

Chen L. ^{[1
]}

Sakai T. ^{[1
,3
]}

Sakamoto S. ^{[1
]}

Kato M. ^{[2
]}

Inoue K. ^{[1
]}

机构：

[1] Department of Cell Biology, Faculty of Science, Saitama University, Urawa

[2] Department of Physiology I, Nippon Medical School, Tokyo

[3] Laboratory of Cell Biology, Department of Regulation Biology, Saitama University, 255 Shimo-ohkubo, Urawa, Saitama

来源：

Pituitary | 1999年 / 2卷 / 3期

关键词：

Calcium; Gonadotropes; Gonadotropin-releasing hormone; LβT-2; cell; Nitric oxide;

D O I：

10.1023/A:1009988808338

中图分类号：

学科分类号：

摘要：

An immortal cell line (LβT-2) with characteristics of gonadotropes, such as LH-containing secretory granules, and LH release responsiveness to GnRH, was used to investigate the effect of GnRH stimulation on nitric oxide (NO) production. RT-PCR analysis showed that mouse nNOS mRNA was expressed in cultured LβT-2 cells. LβT-2 cells were treated with the calcium ionophore, A23187, and NO levels were measured as nitrite using the Griess assay. The data clearly showed that NO production was increased dose-dependently by A23187 treatment (0-10-5 M). Next, changes in the intracellular concentration of ionized calcium ([Ca2+]i) in LβT-2 cells induced by GnRH were analyzed by quantitative fluorescence microscopy, and [Ca2+]i was found to be increased markedly by GnRH treatment. In fact, exposure of LβT-2 cells to increasing concentrations of GnRH from 0 to 10-6 M was found to enhance NO production in a dose dependent manner, with maximal augmentation at 10-6 M. However, the stimulation of NO production by GnRH at this concentration was significantly attenuated by pretreatment with NG- nitro-L-arginine methyl ester hydrochloride (L-NAME), a NO synthase inhibitor. Taken together, the present results suggest that GnRH treatment results in increased NO production in LβT-2 clonal gonadotropes, and intracellular calcium augmentation produced by GnRH may be participate in this process. Our findings also indicate that the LβT-2 cell line is a useful tool for in vitro studies of the autocrine and paracrine roles of NO in the anterior pituitary gland.

引用

页码：191 / 196

页数：5

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