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

同时测定pge_2诱导鸡早孕和吲哚美辛阻断鸡早孕的子宫肌电图活性（EMG）、血浆前列腺素（PG） F、E和精氨酸缩宫素（AVT）浓度。在预测产卵时间前3小时给药吲哚美辛（5mg, im）可使母鸡下蛋延迟8 ~ 14小时，而对照母鸡在预测产卵时间下蛋。在预期的排卵时间内，吲哚美辛处理的母鸡子宫肌电图活性和血浆PGF、PGE和AVT浓度均未观察到增加，而在自发排卵期间，血浆PGF和AVT明显增加。在排卵前3小时宫内给予PGE_2（1<micrn>g）可预测在5 min内诱导早产卵。早孕伴随着子宫肌电图活动和血浆AVT水平的显著升高。血浆PGF和PGE水平未见变化。当诱导早孕时，在子宫内无卵的情况下，在预期的排卵时间观察到肌电图活性和血浆中PGF和AVT浓度的显著增加。经吲哚美辛预处理的蛋鸡在预测产卵时间注射PGE_2，可显著提高血浆AVT水平。结果表明，子宫收缩可刺激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.