The objectives of this study were to determine the plasma profile of equine chorionic gonadotropin (eCG) and its association with the formation of supplementary corpus luteum (CL) and plasma progesterone concentrations in embryo transfer Hokkaido native pony recipient mares. Blood samples and transrectal ultrasound examination of the reproductive tract were carried out weekly from the day of ovulation until week 32 of gestation (n = 4). Plasma concentrations of eCG and progesterone were measured by enzyme immunoassays. The eCG concentration was first detectable at week 5 for 2 mares and at week 6 for another 2 mares. Immediately after detection, the mean plasma eCG concentrations were observed to rise sharply and reach a peak at week 8. The concentrations then declined dramatically to a baseline (<0.5 IU/mL) by week 21. Plasma progesterone p=p concentrations increased in 2 phases. First, a sharp increase from 0.18 ± 0.05 ng/mL at ovulation to 15.9 ± 4.6 ng/mL at week 1 was observed, then a decrease to 9.69 ± 2.27 ng/mL by week 2, and maintained at this level until week 5 of gestation. The onset of the second rise occurred at week 6 and was observed to peak to 58.3 ± 21.8 ng/mL at week 10, then gradually declined to <10 ng/mL by week 26. The supplementary CLs were first detectable by pregnancy week 6 and 7 for 2 mares each. All supplementary and primary CLs regressed by week 26 for 3 mares and by week 30 for the remaining mare. The mean number of supplementary CL was 4.5 ± 0.8 and their formation in the right ovary (66.7%, 12/18) was higher (P < 0.05) than that in the left ovary (33.3%, 6/18). Among the mares, 1 mare that developed only 2 supplementary CL had 35% lower level of peak eCG and 65% lower concentration of peak progesterone compared with other 3 mares that had 5 or 6 supplementary CL. In conclusion, development of supplementary CL and blood concentrations of progesterone from around day 40 of gestation were associated with eCG concentration. The total number of supplementary CL formation in the present study in embryo transfer Hokkaido native pony recipient mares seemed higher than previously reported supplementary CL number in pregnant mares, with a greater rate in the right ovary than in left.

这项研究的目的是确定马绒毛膜促性腺激素（eCG）的血浆分布及其与补充黄体（CL）的形成以及胚胎移植北海道本地小马受体母马中血浆孕酮浓度的关系。从排卵日到妊娠第32周（n = 4），每周进行一次血样和经直肠超声检查。通过酶免疫测定法测定血浆eCG和孕酮的浓度。最初在第5周检测到2个母马，然后在第6周检测另外2个母马的eCG浓度。检测后，立即观察到平均血浆eCG浓度急剧上升并在第8周达到峰值。然后到21周，其浓度急剧下降至基线（<0.5 IU / mL）。血浆孕酮p = p浓度分两个阶段增加。首先，观察到从排卵时的0.18±0.05 ng / mL急剧增加到第1周的15.9±4.6 ng / mL，然后到第2周降低至9.69±2.27 ng / mL，并保持在该水平直到第5周。妊娠。第二次上升的发作发生在第6周，在第10周时达到峰值58.3±21.8 ng / mL，然后到第26周逐渐下降至<10 ng / mL。在怀孕的第6周和7匹2匹母马。在26周之前，所有母马的补充和主要CL均已退化，而其余母马则在30周之前。补充性CL的平均数为4.5±0.8，其在右卵巢的形成率（66.7％，12/18）更高（在第1周时观察到6 ng / mL，然后在第2周时降低到9.69±2.27 ng / mL，并维持在该水平直至妊娠的第5周。第二次上升的发作发生在第6周，在第10周时达到峰值58.3±21.8 ng / mL，然后到第26周逐渐下降至<10 ng / mL。在怀孕的第6周和7匹2匹母马。在26周之前，所有母马的补充和主要CL均已退化，而其余母马则在30周之前。补充性CL的平均数为4.5±0.8，其在右卵巢的形成率（66.7％，12/18）更高（在第1周时观察到6 ng / mL，然后在第2周时降低到9.69±2.27 ng / mL，并维持在该水平直至妊娠的第5周。第二次上升的发作发生在第6周，在第10周时达到峰值58.3±21.8 ng / mL，然后到第26周逐渐下降至<10 ng / mL。在怀孕的第6周和7匹2匹母马。在26周之前，所有母马的补充和主要CL均已退化，而其余母马则在30周之前。补充性CL的平均数为4.5±0.8，其在右卵巢的形成率（66.7％，12/18）更高（然后在第26周逐渐降至<10 ng / mL。在怀孕第6周和第7周首先检测到2匹母马的补充CL。在26周之前，所有母马的补充和主要CL均已退化，而其余母马则在30周之前。补充性CL的平均数为4.5±0.8，其在右卵巢的形成率（66.7％，12/18）更高（然后在第26周逐渐降至<10 ng / mL。在怀孕第6周和第7周首先检测到2匹母马的补充CL。在26周之前，所有母马的补充和主要CL均已退化，而其余母马则在30周之前。补充性CL的平均数为4.5±0.8，其在右卵巢的形成率（66.7％，12/18）更高（P <0.05），高于左卵巢（33.3％，6/18）。在这些母马中，仅发育2个补充CL的母马与其他3个母马具有5个或6个补充CL的母马相比，​​其eCG峰值水平降低了35％，孕激素峰值浓度降低了65％。总之，妊娠40天左右补充补充CL的发展和孕酮的血药浓度与eCG浓度有关。在本研究中，北海道本地小马受体母马胚胎移植中补充CL的总数似乎比先前报道的怀孕母马中的补充CL数目更高，其中右卵巢的比率高于左卵巢。