抗孕53影响大鼠垂体前叶对GnRH的敏感性反应

本实验应用动情前期大鼠垂体前叶组织块离体培养方法,观察了 A 环失碳类甾体化合物—抗孕53对 LH 基础分泌和动员性分泌的影响。实验分为对照组、GnRH 组、抗孕53组、GnRH-抗孕53组。结果表明,GnRH 可显著促进 LH 分泌并产生自激作用。GnRH 的第一次作用后,LH 分泌增加量由对照组的0.7ng/ml 增加到4.3ng/ml,而当 GnRH 第二次作用后,这一效应显著增强,由对照组的0.5ng/ml 增加到6.8ng/ml,GnRH 的两次作用效应相比,差异极显著。抗孕53可部分抑制垂体对 GnRH 的敏感性反应。抗孕53作用后,LH 分泌增加量由 GnRH 第一次作用后的4.3减至2.5ng/ml,由 GnRH 第二次作用后的6.8降至4.1ng/ml。抗孕53不影响 LH 的基础分泌,与对照组相比,两组的 LH 分泌增加量无显著差异。抗孕53对垂体的这一作用可能是通过直接影响促性腺激素细胞的代谢及调节而实现。

EFFECT OF ANORDRIN ON THE RAT ANTERIOR PITUITARY RESPONSIVENESS TO GnRH IN VITRO

The responsiveness of pituitary explant to pulsatile GnRH(in 199 meduim)and the effect of Anordrin on it were determined by RIA of the basal and promotedsecretion of LH.Pituitaries were taken from proestrous rats.Pulsatile GnRHregime consisted of a 6-min pre-exposure to the hormone followed by the dissolvent199 medium only for 54 minutes.The procedure was repeated for another 1 hour.The results showed that a 6-min pulsatile GnRH exposure stimulated release ofLH;the net increase amounts to 4.3ng/ml after the first exposure(and)significant-ly to 6.8ng/ml after the second exposure.Thus GnRH is capable of not only sti-mulating pituitary explant to produce LH but also showing some priming effect.Anordrin did not influence basal LH secretion but did partially inhibit GnRH in-duced release of LH from 4.3 to 2.5ng/ml in the first hour and from 6.8 to 4. lng/ml in the second hour(P>0.01).