Van Cleeff J, Karsch F J, Padmanabhan V
Reproductive Sciences Program, University of Michigan, Ann Arbor 48109-0404, USA.
Domest Anim Endocrinol. 1998 Jan;15(1):23-34. doi: 10.1016/s0739-7240(97)00059-3.
The Controlled Internal Drug Releasing (CIDR) device is an intravaginal pessary containing progesterone (P4) designed for synchronizing estrus in ruminants. To date, there has been little information available on the timing, duration, and quality of the follicular phase after CIDR removal and how those characteristics compare with natural periovulatory endocrine events. The present communication relates the results of methods we used to characterize the endocrine events that followed CIDR synchronization. Breeding-season ewes were given an injection (10 mg) of Lutalyse (PGF2 alpha), and then studied during three consecutive estrous cycles, beginning in the luteal phase after the estrus induced by PGF2 alpha. Cycle 1 estrus was synchronized with 1 CIDR (Type G) inserted for 8 d beginning 10 d after PGF2 alpha. Cycles 2 and 3 were synchronized with two CIDRs for 8 d beginning 10 d after previous CIDR removal. Cycle 1 estrous behavior and serum gonadotropins showed a follicular phase (the interval from CIDR withdrawal to gonadotropin surge [surge] peak) of 38.2 +/- 1.5 hr. Two CIDRs lengthened the interval to 46.2 +/- 1.5 hr (P < 0.0001). At CIDR removal, circulating P4 concentrations were higher in ewes treated with two CIDRs (5.1 +/- 0.3 and 6.4 +/- 0.4 ng/mL in Cycles 2 and 3 vs. 2.7 +/- 0.3 ng/mL in Cycle 1), whereas estradiol concentrations were higher in the 1 CIDR cycle (3.3 +/- 0.5 pg/mL in Cycle 1 vs. 0.5 +/- 0.1, and 0.7 +/- 0.2 pg/mL in Cycles 2 and 3), suggesting that the lower levels of P4 achieved with one CIDR was not sufficient to arrest follicular development. There were no differences in any other endocrine variable. Both one and two CIDR synchronization concentrated surges within a 24-hr period in 92% of the ewes in Cycles 1 and 2. Cycles 3 ewes were euthanized at estimated luteal, early follicular, late follicular, LH surge, and secondary FSH rise timepoints. Endocrine data and ovaries showed that 88% of the ewes synchronized with two CIDRs were in the predicted stage of the estrous cycle. These data demonstrate that the CIDR device applied during the luteal phase effectively synchronizes estrus and results in a CIDR removal-to-surge interval of similar length to a natural follicular phase.
可控性内药物释放（CIDR）装置是一种阴道栓剂，含有用于使反刍动物发情同步的孕酮（P4）。迄今为止，关于CIDR取出后卵泡期的时间、持续时间和质量，以及这些特征与自然排卵前内分泌事件相比情况的信息很少。本通讯介绍了我们用于表征CIDR同步后内分泌事件的方法的结果。繁殖季节的母羊注射（10毫克）氯前列烯醇（PGF2α），然后在连续三个发情周期进行研究，从PGF2α诱导发情后的黄体期开始。第1周期发情通过在PGF2α后10天开始插入1个CIDR（G型）8天来同步。第2和第3周期通过在前一个CIDR取出后10天开始插入两个CIDR 8天来同步。第1周期发情行为和血清促性腺激素显示卵泡期（从CIDR取出到促性腺激素激增[激增]峰值的间隔）为38.2±1.5小时。两个CIDR将间隔延长至46.2±1.5小时（P<0.0001）。在取出CIDR时，用两个CIDR处理的母羊循环P4浓度较高（第2和第3周期分别为5.1±0.3和6.4±0.4纳克/毫升，而第1周期为2.7±0.3纳克/毫升），而第1个CIDR周期中雌二醇浓度较高（第1周期为3.3±0.5皮克/毫升，第2和第3周期为0.5±0.1和0.7±0.2皮克/毫升），这表明用一个CIDR达到的较低P4水平不足以阻止卵泡发育。在任何其他内分泌变量方面没有差异。在第1和第2周期中，92%的母羊使用一个和两个CIDR同步都将激增集中在24小时内。第3周期母羊在估计的黄体期、卵泡早期、卵泡晚期、LH激增和继发性FSH上升时间点实施安乐死。内分泌数据和卵巢显示，88%用两个CIDR同步的母羊处于发情周期的预测阶段。这些数据表明，在黄体期应用CIDR装置可有效使发情同步，并导致从CIDR取出到激增的间隔与自然卵泡期长度相似。
