Absence of increased hypothalamic nitric oxide synthase gene expression during the preovulatory LH surge in middle-aged rats.
Absence of increased hypothalamic nitric oxide synthase gene expression during the preovulatory LH surge in middle-aged rats.
复制标题
中年大鼠排卵前 LH 激增期间下丘脑一氧化氮合酶基因表达不增加。
DOI：
10.1097/00001756-199812210-00006
复制
发表时间：
1998
期刊：
影响因子：
1.7
通讯作者：
Sahu,A
中科院分区：
文献类型：
--
作者：
Sahu,A
本研究旨在验证中年（MA）大鼠排卵前促黄体生成激素（LH）峰减少可能与一氧化氮（NO）能神经元活性改变有关的假设。为了开始检验这一假设，在青年（2-3月龄）和中年（MA，8-10月龄）大鼠发情前期检测了下丘脑NO合酶（NOS）（催化NO产生的酶）的基因表达。与10.00 h相比，幼鼠12.00 h NOS mRNA水平显著升高，LH峰出现在16.00 h。在MA大鼠，相反，有没有变化，NOS mRNA水平之间的上午和下午的时间与延迟和衰减LH峰。这些结果表明，下丘脑NOS基因的表达增加，早在年轻大鼠的LH激增，这在NOS基因表达的先行增加不会发生在MA定期循环大鼠。由于下丘脑NO能神经元参与LH释放激素（LHRH）和LH浪涌的诱导，我们的研究结果表明，减少LH浪涌MA大鼠可能，部分是由于在这些动物中的NOS神经元活性的改变。
THIS study was performed to test the hypothesis that diminution in the preovulatory luteinizing hormone (LH) surge in middle-aged (MA) rats may be related to altered activity in nitric oxide (NO) ergic neurons. To begin to test the hypothesis, gene expression of hypothalamic NO synthase (NOS), the enzyme that catalyzes NO production, was examined on the day of proestrus in young (2–3 months old) and middle-aged (MA, 8–10 months old) rats. Compared with those at 10.00 h, NOS mRNA levels were increased significantly at 12.00 h and the LH surge occurred at 16.00 h in young rats. In MA rats, in contrast, there was no change in NOS mRNA levels between morning and afternoon hours in association with a delayed and attenuated LH surge. These results show that hypothalamic NOS gene expression increases long before the LH surge in young rats and that this antecedent increase in NOS gene expression does not occur in MA regularly cycling rats. Since hypothalamic NOergic neurons participate in induction of LH-releasing hormone (LHRH) and LH surges, our results suggest that reduced LH surges in MA rats may, in part, be due to altered NOS neuronal activity in these animals.