Aglepristone (RU 46534) is a competitive progesterone antagonist that is indicated for the treatment of various progesterone-dependent physiological or pathologic conditions. Aglepristone has proven to be an effective means of terminating pregnancy in most species. When used to induce parturition, aglepristone was effective in all cases in the bitch, cow, and goat, with no apparent adverse effects on neonatal health or milk production. When used to schedule an elective cesarean section, aglepristone treatment was deemed safe for dams and puppies, providing that the ovulation date had been accurately assessed at the time of breeding. Irrespective of the stage of pregnancy at injection, treatment with aglepristone has no apparent negative effects on subsequent fertility. Aglepristone is also a safe and relatively effective means of treating pyometra. However, given the high level of septic risk and the likelihood of rapid deterioration, such therapy is not recommended in emergency situations. Treatment of feline fibroadenomatosis using aglepristone has given promising results, but repeat treatment may be necessary in cats previously treated with long-acting progestagens. The use of aglepristone in other progesterone-dependent diseases has yet to be fully evaluated but may prove valuable, especially in the treatment of insulin-resistant diabetes mellitus, acromegaly, and the treatment of some vaginal tumors in the bitch.
Summary
The purpose of this study was to evaluate the exact age when the equine embryo reaches the uterus. The time of ovulation was determined by hourly ultrasound examinations starting 32 h after an injection of crude equine pituitary gonadotrophin or human chorionic gonadotrophin, or after the first of 4 injections of buserelin. Nonsurgical uterine flushings were carried out 144 h (Day 6), 156 h (Day 6.5) or 168 h (Day 7) after ovulation. Induction of ovulation was attempted in 101 oestrous cycles and 61 of 101 mares (60.4%) ovulated 32–44 h post injection. Sixty embryo collections were performed which yielded: 0/20 embryos at 144 h, 9/17 embryos (53%) at 156 h and 12/23 embryos (52%) at 168 h. The mean (± s.e.m.) diameter of the embryo was significantly greater (P < 0.01) at Day 7 (244 ± 15 μm) than at Day 6.5 (186 ± 9.1 μm), and variability in size was observed among embryos collected from the same mare after synchronous natural multiple ovulations.
These results suggest that; i) horse embryos enter the uterus between 144 and 156 h after ovulation, and ii) the time interval between ovulation and fertilisation in mares is inconsistent and/or embryonic development rate may differ between individual embryos.
Contents
Pyometra is a reproductive disorder very common in bitches over 8 years of age in which physiological effects of progesterone on the uterus play a major role. The traditional therapy for pyometra is ovariohysterectomy. The main advantage of ovariohysterectomy over medical management is that it is both curative and preventive for recurrence of pyometra. However, surgery is associated with the risk of anaesthesia and renders the bitch sterile. During the last 10 years, numerous medical treatments have been proposed to treat both open and closed cervix pyometra. The most effective medical treatment with minor side effects seems to be the repeated administration of aglepristone with or without the additional treatment with low doses of prostaglandins.
To evaluate the efficacy and safety of aglepristone 15 mg kg(-1) for induction of parturition in bitches, 22 pregnant beagle bitches were injected subcutaneously on day 60 post-estimated LH surge, and again 24 h later with aglepristone and subsequently were given 0.15 IU kg(-1) oxytocin at hourly intervals until delivery of the last puppy. Six pregnant beagle bitches were used as a non-treated control group. In the control group, parturition occurred at 63.2 +/- 0.5 days, 29 pups were born and the average expulsion time per puppy was 1.0 +/- 0.6 h. In the treated group, parturition was obtained on average 29.7 +/- 5.6 h after aglepristone administration, 121 pups were born and average expulsion time per pup was 1.1 +/- 0.4 h. The percentage of live puppies, 7 weeks after birth, was 86.1% (25/29) and 86.8% (105/121) for the control and treated groups, respectively. No significant difference was observed between the control and treated groups for the average expulsion time per live puppy and for the percentage of live puppies at birth, 48 h, 7 days or 7 weeks after birth (p > 0.05). This study confirms previous results and demonstrates that the combination of aglépristone and oxytocin can be safely and reliably used to induce parturition in beagle bitches, at 60 days post-estimated LH surge.
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