Aglepristone was administered in bitches during the follicular phase to evaluate its effects on progesterone, estradiol‐17β and LH serum concentrations. Ten German Shepherds were divided into two groups (treated n = 5; control n = 5). Treated bitches received 10 mg/kg BW of aglepristone subcutaneously during the early follicular phase, 24 hr after and then 7 days later. The control group was injected, at the same time periods, with saline solution (0.3 ml/kg BW). For the steroid evaluations, blood was collected daily from the onset of proestrus until the first day of cytological dioestrus. For LH base‐line serum determination, blood was also collected every 20 min for 2 hr at the onset of proestrus. For LH surge identification, blood was collected daily (every 6 hr) starting from the day of the first administration of aglepristone or saline solution until the first day of dioestrus. All animals ovulated but the treated group presented longer ovulation‐dioestrus intervals than the control group (5.2 ± 2.2 days p < .05). Serum concentrations of the evaluated hormones were similar between experimental animals except for serum LH. Indeed, no LH peaks were detected in the treated group while LH surges were clearly observed in the control group (9 ± 1 days after the beginning of proestrus. In particular, the area under the curve for LH was significantly lower in treated than control animals (12 ± 4 ng/ml x Day; p = .01). In conclusion, administrations of aglepristone during the follicular phase of the bitch does not affect the steroid hormone patterns but does prevent the occurrence of a LH surge. This work raises significant questions and opens perspectives concerning the mechanisms of ovulation in bitches.

中文翻译：

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卵泡期给予aglepristone（RU534）对雌性黄体酮，雌二醇17β和LH血清浓度的影响

卵泡期在母犬中施用阿格列斯通，以评估其对孕酮，雌二醇-17β和LH血清浓度的影响。十只德国牧羊犬分为两组（治疗组n  = 5；对照组n = 5）。在卵泡早期，24小时后和7天后，皮下接受治疗的母犬皮下注射10 mg / kg体重的aglepristone。对照组同时注射生理盐水（0.3 ml / kg BW）。对于类固醇的评估，从发情期开始直到细胞学发情期的第一天每天收集血液。为了测定LH基线血清，在发情期开始时每20分钟还采集一次血液，共2小时。为了进行LH潮气识别，从首次服用aglepristone或盐水溶液的那一天开始到发情的第一天，每天（每6小时）收集一次血液。所有动物排卵，但治疗组的排卵期-发情间隔比对照组长（5.2±2.2天p <.05）。在实验动物之间，血清LH的血清激素浓度相似。实际上，在治疗组中未检测到LH峰，而在对照组中（在发情期开始后9±1天）明显观察到LH激增。特别是，治疗后的LH曲线下面积明显低于对照组动物（12±4 ng / ml x天；p  = 0.01）。总之，在卵泡卵泡期给予aglepristone不会影响类固醇激素的作用，但可以防止LH激增的发生。质疑并打开有关母犬排卵机制的观点。