GnRH－A诱导泰和鸡母鸡排卵的生殖内分泌机制

A STUDY ON THE REPRODUCTIVE ENOOCRINE MECHANISMS OF OVULATIONINDUCED BY [D-Leu￣6 ,Pro9]-GnRH N-ETHYLAMIDE IN LAYING TAIHE RENS

本试验研究了促性腺激素释放激素类似物───［Ｄ－Ｌｅｕ￣６，Ｐｒｏ￣９］－ＧｎＲＨＮ－乙酰胺（ＧｎＲＨ－Ａ）诱导泰和鸡母鸡排卵的生理效应，藉此探讨其生殖内分泌机制。结果表明：（１）ＧｎＲＨ－Ａ具有显著刺激母鸡生殖器官发育的效应，导致母鸡卵巢、输卵管以及肝重增加（Ｐ＜０．０１），但对鸡体重没有显著的影响（Ｐ＜０．０５）；产蛋停止前１周施用ＧｎＲＨ－Ａ可维持母鸡正常产蛋的生殖生理状态。（２）ＧｎＲＨ－Ａ给药后最初２０ｄ诱发出两个鸡血浆促黄体生成素（ＬＨ）释放峰，处理组（ＧｎＲＨ－Ａ组）血浆ＬＨ浓度在此期间显著高于对照组（Ｐ＜０．０１）；然而与对照组相比较，处理组鸡血浆促卵泡素（ＦＳＨ）却没有明显变化（Ｐ＜０．０５）。（３）鸡血浆孕酮（Ｐ４）浓庆在施用ＧｎＲＨ－Ａ后明显上升，显著高于尚处休产期的对照组（Ｐ＜０．０１）。与此相反，给药后的囊初８ｄ内，鸡血浆雌二醇（Ｅ２）浓度明显降低，虽然随后略有回升，但仍低于对照组（Ｐ＜０．０１）。据此可以认为，ＧｎＲＨ－Ａ诱导卵巢和输卵管发育与鸡血浆ＬＨ、Ｐ４以及Ｅ２浓度变化密切相关，ＧｎＲＨ－Ａ是一种有效的制剂。

Ovulation induced by gonadotropin - releasing bormone agonist [GnRH-A , (D - Leu6 ,Pro9)-GnRH N-ethylamide] was used as a model for studying the endocrine mechanisms ofovulation in laying Taibe beus. The results showed that : (1) GnRH-A had a great stimulat-ing effect on development of reproductive organs of hens, and caused weight increasing ofovary , oviduct and liver in hens, whereas there was no siguificant weight difference betweenGnRH-A and control group. Adminstration of GnRH-A seven days before the end of layingcould keep normal egg production of the hens. (2) Twenty days after GnRH-A administra-tion the two releasing peaks of plasma LR were induced in GnRH-A group, and plasma LHconcentrations were higber in GnRH-A group than that in control group, whereas plasmaFSH did uot changed significantly compared witk control group. (3) After administratiou ofGnRH-A, plasma progesterone increased , aud it was higher in GnRR-A group than that incontrol group out of laying cycle. On contary, plasma estriol declined obviously 8 days afterGnRH-A administration, though it elevated slightly later, it was less than that in controlgroup. It is concluded that GnRH-A inducetl oviduct and ovaiution developinent is associatedwith changes in plasina LH , progesterone and estriol concentration and that GnRH-A may bean useful ageut for inducing development of ovalution and oviduct and improving egg produc-tion .