Coordinating mechanisms of prostaglandins and vasotocin in the control of ovulation-oviposition

同时测定了子宫肌电活动(EMG)、血浆前列腺素(PG)F、E和精氨酸加压素(AVT)浓度与PGE_2诱导的雏鸡早产和吲哚美辛阻断产卵的关系。在预计产卵时间前3小时注射吲哚美辛(5 mg，im)可使产蛋延迟8~14小时，而对照组母鸡按预计时间下蛋。在吲哚美辛处理的母鸡中，子宫肌电活动和血浆PGF、PGE和AVT浓度在预期产卵时间没有观察到增加，而血浆PGF和AVT浓度在自然产卵期间显著增加。预测产卵前3小时宫内注射前列腺素E_2(1&lt；microrn&gt；g)可在5分钟内产下早产卵。早产伴随着子宫肌电活动和血浆AVT水平的显著升高。未观察到血浆PGF和PGE水平的变化。在诱导提前产卵时，子宫内没有卵子的情况下，在预期产卵时间，肌电活动和血浆PGF和AVT浓度显著增加。在预测的产卵时间给予前列腺素E_2可诱导母鸡产卵，同时伴随血浆AVT水平的显着升高。结果表明，鸡子宫收缩刺激AVT的释放。

Uterine electromyographic activity (EMG),plasma concentrations of prostaglandin(PG) F and E, and arginine vasotocin(AVT) were simultaneously measured in relation to PGE_2-induced premature oviposition and to indomethacin-blocked oviposition in chickens. The administration of indomethacin (5 mg, im) 3 hr before the predicted time of oviposition delayed egg lay by 8-14 hr, whereas control hens laid eggs at the predicted time. In indomethacin-treated hens increases in uterine EMG activity and plasma concentrations of PGF,PGE,and AVT were not observed at the expected time of oviposition, whereas a marked increase in plasma PGF and AVT occurred during spontaneous oviposition . The intrauterine administration of PGE_2(1<micrn>g) 3 hr before predicted oviposition induced premature egg lay within 5 min. Premature oviposition was accompanied by significant elevations in both uterine EMG activity and plasma levels of AVT. Changes in plasma levels of PGF and PGE were not observed. When premature oviposition was induced, significant increases in EMG activity and plasma concentrations of PGF and AVT were observed at the expected time of oviposition in the absence of an egg in the uterus. The administration of PGE_2 at the predicted time of oviposition in hens pretreated with indomethacin induced oviposition which was accompanied by a significant increase in plasma AVT levels. The results suggest that AVT release is stimulated by uterine contractility in chickens.