Phosphodiesterase expression targeted to gonadotropin-releasing hormone neurons inhibits luteinizing hormone pulses in transgenic rats-猫眼课题宝

靶向促性腺激素释放激素神经元的磷酸二酯酶表达抑制转基因大鼠中的黄体生成素脉冲

DOI：

发表时间：

2002

期刊：

Proceedings of the National Academy of Sciences of the United States of America

影响因子：

11.1

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

S. Paruthiyil;M. Majdoubi;M. Conti;R. Weiner

Experiments in the GT1 gonadotropin-releasing hormone (GnRH) cell line have shown that the cAMP signaling pathway plays a central role in regulating the excitability of the cells. Lowering cAMP levels by expressing the constitutively active cAMP-specific phosphodiesterase PDE4D1 in GT1 cells inhibited spontaneous Ca2+ oscillations and intrinsic pulsatile GnRH secretion. To address the role of cAMP levels in endogenous GnRH neurons, we genetically targeted expression of PDE4D1 (P) to GnRH neurons in transgenic rats (R) by using the GnRH gene promoter/enhancer regions (G). Three lines of transgenic rats, GPR-2, -4, and -5, were established. In situ hybridization and RT-PCR studies demonstrated that transgene expression was specifically targeted to GnRH neurons. Decreased fertility was observed in female but not in male rats from all three lines. The mean luteinizing hormone (LH) levels in ovariectomized rats were significantly reduced in the GPR-4 and -5 lines but not in the GPR-2 line. In castrated male and female GPR-4 rats, the LH pulse frequency was dramatically reduced. Six of twelve GPR-4 females studied did not ovulate and had polycystic ovaries. The remaining six females ovulated, but the magnitude of the preovulatory LH surge was inhibited by 63%. These findings support the hypothesis that cAMP signaling may play a central role in regulating excitability of GnRH neurons in vivo. The GPR-4 line of transgenic rats provides a genetic model for the understanding of the role of pulsatile gonadotropin release in follicular development.