Oxytocin has a role in gonadotrophin regulation in rats.
Oxytocin has a role in gonadotrophin regulation in rats.
复制标题
催产素在大鼠促性腺激素调节中发挥作用。
作者：
G. Robinson;J. Evans
我们以前证明，催产素刺激LH从大鼠垂体细胞在体外释放，并在体内小鼠卵泡发育和排卵的进步。本研究报告了大鼠LH水平的调查后，在体内给药催产素。注射催产素（10 mIU/g，i. p.）在动情前期07.00、08.00、09.00 h或动情前期09.00、10.00、11.00 h，大鼠外周血LH峰的出现时间和峰值浓度均提前（P <0.005）。另一方面，LH峰的下降相和峰幅度不被催产素改变。在发情前05.00、06.00和07.00 h或发情前11.00、12.00和13.00 h给药对LH特征无影响。较高的催产素剂量（20 mIU/g）抑制LH的释放时，治疗开始于05.00，07.00或09.00小时的发情前期。较低剂量（5 mIU/g）对改变LH浓度无效。此外，注射催产素（10 mIU/g）在发情期，发情后期或间情期对LH的释放没有影响。因此，催产素在改变LH浓度方面的功效是剂量依赖性的，并且还受到发情周期的日期和发情前期的时间的严重影响。去除内源性催产素活性的催产素受体拮抗剂的使用废除了促动情LH峰，表明催产素是一个重要的生理成分的LH释放机制在大鼠。这项研究提供了明确的证据，催产素诱导LH释放在体内，但催产素活性的表现是依赖于暴露条件。
We previously demonstrated that oxytocin stimulates LH release from rat pituitary cells in vitro and advances follicular development and ovulation in mice in vivo. This study reports an investigation of rat LH levels following in-vivo administration of oxytocin. Injection of oxytocin (10 mIU/g, i.p.) to rats at 07.00, 08.00 and 09.00 h of pro-oestrus or at 09.00, 10.00 and 11.00 h of pro-oestrus advanced the onset of the LH surge (P less than 0.005) and attainment of peak concentrations of LH (P less than 0.02) in peripheral blood. On the other hand, the descending phase of the LH surge and the surge amplitude were not altered by oxytocin. Treatment at 05.00, 06.00 and 07.00 h of pro-oestrus or at 11.00, 12.00 and 13.00 h of pro-oestrus had no effect on the LH profile. A higher oxytocin dose (20 mIU/g) inhibited LH release when treatment was begun at 05.00, 07.00 or 09.00 h of pro-oestrus. A lower dose (5 mIU/g) was ineffective in altering LH concentrations. In addition, injections of oxytocin (10 mIU/g) at oestrus, metoestrus or dioestrus had no effect on the release of LH. Thus the efficacy of oxytocin in altering concentrations of LH was dose dependent and also critically affected by the day of the oestrous cycle and the time of pro-oestrus. Removal of endogenous oxytocin activity by the use of an oxytocin receptor antagonist abolished the pro-oestrous LH surge, indicating that oxytocin is a vital physiological component of the LH-releasing mechanism in rats. The study provides unequivocal evidence that oxytocin induces LH release in vivo, but the manifestation of oxytocin activity is dependent upon conditions of exposure.