Chaturvedi Chandra Mohini, Kumar Pankaj
Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.
Gen Comp Endocrinol. 2007 May 1;151(3):285-99. doi: 10.1016/j.ygcen.2007.01.024. Epub 2007 Jan 30.
Nitric oxide (NO) a gaseous neurotransmitter is reported to play an important role in controlling the release of luteinizing hormone releasing hormone (LHRH) in mammalian system. But its role has not been investigated in birds, where photoperiod plays an important role in regulating gonadal development. To investigate the effect of NO on gonadal and adrenal function of Japanese quail, in the first experiment, 3-weeks-old sexually immature quail received NO donor sodium nitroprusside (SNP, 5mg/100g body weight) orally or nitric oxide synthase (NOS) inhibitor N-nitro L-arginine methyl ester (L-NAME, 25 microg/100g body weight) intraperitoneally for 13 days in continuous condition of light (LL). Thereafter treated quail along with their respective controls were shifted to long day length (LD 16:8) for 21 days when the study was terminated. Results indicate that SNP treatment stimulated and L-NAME suppressed body weight, cloacal gland volume (an androgen dependent sex accessory organ), testes (gonado-somatic index, spermatogenesis), epididymis (histology) and adrenal (weight, histology, cortico-medullary ratio) function as well as total nitrite and nitrate concentration in plasma, hypothalamus and testes. In the second experiment, two groups of 3-weeks-old birds were maintained in short day length (LD 6:18) or long day length (LD 16:8) for 5 weeks to induce gonadal suppression and stimulation, respectively. Thereafter birds of both the photoperiod were divided into two subgroups, the short day quail receiving normal saline (SD Con) or SNP (SD+SNP) while long day quail received normal saline (LD Con) or L-NAME (LD+L-NAME) for 13 days and were maintained in their respective photoperiods, until the termination of study (21 days post treatment period). SNP stimulated all the parameters even in short day condition and L-NAME suppressed in long day quail compared to their respective controls. These findings indicate positive control of NO on the gonad and adrenal function of Japanese quail which exhibits parallel adrenal-gonad relationship. Further, NO donor induces long day effects while NOS inhibitor mimics short day effects. It is concluded that NO may not only regulate hypothalamo-hypophyseal-gonadal and -adrenal axis of Japanese quail but may also modulate its photosexual responses.
一氧化氮（NO）作为一种气态神经递质，据报道在哺乳动物系统中对促黄体生成素释放激素（LHRH）的释放控制起着重要作用。但在鸟类中其作用尚未得到研究，而在鸟类中光周期对性腺发育起着重要调节作用。为了研究NO对日本鹌鹑性腺和肾上腺功能的影响，在第一个实验中，3周龄性未成熟的鹌鹑在持续光照（LL）条件下，口服NO供体硝普钠（SNP，5mg/100g体重）或腹腔注射一氧化氮合酶（NOS）抑制剂N-硝基-L-精氨酸甲酯（L-NAME，25μg/100g体重），持续13天。此后，将处理过的鹌鹑及其各自的对照组转移到长日照（LD 16:8）条件下21天，此时研究结束。结果表明，SNP处理刺激而L-NAME抑制体重、泄殖腔腺体积（一种雄激素依赖的性附属器官）、睾丸（性腺-体指数、精子发生）、附睾（组织学）和肾上腺（重量、组织学、皮质-髓质比）功能以及血浆、下丘脑和睾丸中的总亚硝酸盐和硝酸盐浓度。在第二个实验中，两组3周龄的鸟分别在短日照（LD 6:18）或长日照（LD 16:8）条件下饲养5周，以分别诱导性腺抑制和刺激。此后，两个光周期组的鸟都被分成两个亚组，短日照鹌鹑接受生理盐水（SD Con）或SNP（SD+SNP），而长日照鹌鹑接受生理盐水（LD Con）或L-NAME（LD+L-NAME），持续13天，并维持在各自的光周期条件下，直到研究结束（处理后21天）。与各自的对照组相比，SNP即使在短日照条件下也能刺激所有参数，而L-NAME在长日照鹌鹑中则起抑制作用。这些发现表明NO对日本鹌鹑的性腺和肾上腺功能具有正向调控作用，呈现出平行的肾上腺-性腺关系。此外，NO供体诱导长日照效应，而NOS抑制剂模拟短日照效应。得出的结论是，NO不仅可能调节日本鹌鹑的下丘脑-垂体-性腺和-肾上腺轴，还可能调节其光性反应。
