Aba M A, Forsberg M, Kindahl H, Sumar J, Edqvist L E
Department of Clinical Chemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Acta Vet Scand. 1995;36(4):489-98. doi: 10.1186/BF03547663.
Plasma concentrations of oestradiol-17 beta, progesterone, 15-keto-dihydro-PGF2 alpha and luteinizing hormone (LH) were monitored in llamas and alpacas after mating with an intact male. Concentrations of LH and PGF2 alpha metabolite were high immediately after copulation. Ovulation occurred in 92% of the animals. The first significant increases in progesterone were recorded on day 4 after mating. In non-pregnant animals the lifespan of the corpus luteum was estimated to be 8-9 days. Luteolysis occurred in association with the release of PGF2 alpha. In pregnant animals, a transient decrease in progesterone concentrations was observed between days 8 and 18 in both species. No significant changes in PGF2 alpha secretion were registered during this period. Oestradiol-17 beta concentrations were high on the day of mating, declined to low values on day 4, and started to increase again on day 8. Peak values after luteolysis in non-pregnant animals were significantly higher than those registered in pregnant ones. Furthermore, concentrations of oestradiol-17 beta were elevated for a longer period in non-pregnant than in pregnant animals. The results suggest that progesterone from the corpus luteum exerts a negative influence on follicular activity in pregnant animals by reducing oestradiol-17 beta secretion.
在与完整雄性交配后，对美洲驼和羊驼的血浆中雌二醇-17β、孕酮、15-酮-二氢-PGF2α和促黄体生成素（LH）的浓度进行了监测。交配后立即，LH和PGF2α代谢物的浓度很高。92%的动物发生了排卵。交配后第4天记录到孕酮的首次显著升高。在未怀孕的动物中，黄体的寿命估计为8-9天。黄体溶解与PGF2α的释放有关。在怀孕的动物中，两种动物在第8天至第18天之间都观察到孕酮浓度的短暂下降。在此期间，PGF2α分泌没有显著变化。交配当天雌二醇-17β浓度很高，第4天降至低值，第8天又开始再次升高。未怀孕动物黄体溶解后的峰值显著高于怀孕动物。此外，未怀孕动物中雌二醇-17β浓度升高的时间比怀孕动物更长。结果表明，黄体分泌的孕酮通过减少雌二醇-17β的分泌，对怀孕动物的卵泡活动产生负面影响。
