McKinnon A O, Squires E L, Carnevale E M, Hermenet M J
Theriogenology. 1988;29(5):1055-63. doi: 10.1016/s0093-691x(88)80029-3.
Embryo transfer into ovariectomized steroid-treated mares was used as a model to evaluate various progestin/estradiol treatments and to determine the level of progesterone necessary for the maintenance of pregnancy in mares. Once a donor mare was in estrus and had a >/=35 mm follicle, an ovariectomized recipient was selected and assigned to one of three groups: 1) 1 mg estradiol (E(2)) was injected subcutaneously daily until the donor mare ovulated; on the day of the donor mare's ovulation, daily intramuscular injections of 300 mg progesterone (P4) were commenced and continued until the end of the experiment (Day 35); 2) E(2) and P4 treatments were identical except E(2) was continued daily until Day 20; and 3) The same E(2) treatment as Group 1, 0.044 mg altrenogest per kilogram body weight were administered daily until Day 35. Embryos were recovered 7 d after the donor mare's ovulation and were transferred via surgical flank incision. Twenty additional embryos (controls) were transferred into intact recipients that ovulated 1 d before to 3 d after the donor. Pregnancy rates did not differ (P>0.05) among groups at Days 14 or 35. Pregnancy rates at Day 35 for mares administered injectable P4 (70%) were identical to those given altrenogest. Overall, pregnancy rates for ovariectomized-progestin treated recipients (28 of 40, 70%) were similar (>0.05) to that of intact mares (16 of 20, 80%). Dose of P4 was decreased in Groups 1 and 2 to 200 mg (Days 35 to 39), 100 mg (Days 40 to 44), 50 mg (Days 45 to 49) and 0 mg (>/=Day 50). Blood samples were collected once on Days 34, 35, 39, 40, 44, 45, 49 and 50 and assayed for P4. Dose of altrenogest was decreased to 0.022, 0.011, 0.0055 and 0 mg per kilogram body weight at Days 35 to 39, 40 to 44, 45 to 49 and >/=50. Number of mares in Groups 1 and 2 that lost their pregnancy while given 200, 100, 50 or 0 mg P4 was 0, 2, 8 and 4, respectively. Doses of 0.022, 0.011, 0.0055 and 0 mg altrenogest per kilogram body weight resulted in 0, 6, 4 and 3 mares aborting. Fetal death did not occur until concentrations of P4 decreased below 2.56 ng/ml 24 h after injection.
将胚胎移植到经卵巢切除和类固醇处理的母马体内，以此作为一种模型来评估各种孕激素/雌二醇处理方法，并确定维持母马妊娠所需的孕酮水平。一旦供体母马发情且有一个直径≥35毫米的卵泡，就选择一头经卵巢切除的受体母马，并将其分配到三个组中的一组：1）每天皮下注射1毫克雌二醇（E₂），直至供体母马排卵；在供体母马排卵当天，开始每天肌肉注射300毫克孕酮（P₄），并持续到实验结束（第35天）；2）E₂和P₄的处理方式相同，只是E₂持续每天注射至第20天；3）与第1组相同的E₂处理方式，每天每千克体重给予0.044毫克烯丙孕素，直至第35天。在供体母马排卵7天后回收胚胎，并通过手术侧腹切口进行移植。另外20个胚胎（对照组）被移植到在供体母马排卵前1天至排卵后3天排卵的未切除卵巢的受体母马体内。在第14天或第35天，各组之间的妊娠率没有差异（P>0.05）。接受注射用P₄的母马在第35天的妊娠率（70%）与给予烯丙孕素的母马相同。总体而言，经卵巢切除并用孕激素处理的受体母马的妊娠率（4中的28，70%）与未切除卵巢的母马（20中的16，80%）相似（>0.05）。第1组和第2组中P₄的剂量在第第35至39天降至200毫克、第40至44天降至100毫克、第45至49天降至50毫克、≥第50天降至0毫克。在第34、35、39、40、44、45、49和50天各采集一次血样，并检测P₄。在第35至39天、40至44天、45至49天和≥50天，烯丙孕素的剂量分别降至每千克体重0.022、0.011、0.0055和0毫克。在第1组和第2组中，给予20
