Departamento de Reproducción, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, DF, Mexico.
Anim Reprod Sci. 2012 Jan;130(1-2):57-62. doi: 10.1016/j.anireprosci.2012.01.001. Epub 2012 Jan 21.
The role of eCG during pregnancy was evaluated through the study of the temporal relationships between changes in eCG and progesterone concentrations and the formation of supplementary corpora lutea (SCL) in mares impregnated with donkey semen (mule pregnancies) or with horse semen (equine pregnancies). Concentrations of eCG were higher (p<0.01) in equine than in mule pregnancies between weeks 6.5 and 13. Progesterone concentrations were higher in equine than in mule pregnancies between weeks 9 and 17. All animals developed at least one SCL, but more SCL accumulated during equine pregnancies than during mule pregnancies (1.9 ± 0.2 vs 1.2 ± 0.1; p<0.01). In equine pregnancies, the mares that formed a second SCL had higher eCG concentrations (p<0.05) during the two weeks preceding its formation than those mares remaining with only one SCL. Mares that formed a third SCL had higher (p<0.5) eCG levels than those remaining with one or two SCL. Mares with equine pregnancies that formed three SCL had higher progesterone concentrations (p<0.05) than those that formed only one or two SCL. No differences were found in progesterone or eCG concentrations between mares with mule pregnancies that accumulated different numbers of SCL during pregnancy (p>0.05). It is concluded that eCG stimulates both the development of new SCL and the function of existing CL. While these effects are clearly expressed in mares impregnated by horses, the low eCG concentrations during mule pregnancies reduce the impact of this hormone on CL formation and function.
本研究旨在评估妊娠期间 eCG 的作用，通过研究马妊娠（驴交配的骡子妊娠或马交配的马妊娠）中 eCG 和孕酮浓度的变化与补充黄体（SCL）形成之间的时间关系来评估。在第 6.5 至 13 周，马妊娠的 eCG 浓度明显高于骡子妊娠（p<0.01）。在第 9 至 17 周，马妊娠的孕酮浓度明显高于骡子妊娠。所有动物均至少形成了一个 SCL，但马妊娠中形成的 SCL 多于骡子妊娠（1.9 ± 0.2 比 1.2 ± 0.1；p<0.01）。在马妊娠中，形成第二个 SCL 的母马在其形成前两周的 eCG 浓度明显高于只有一个 SCL 的母马（p<0.05）。形成第三个 SCL 的母马的 eCG 水平明显高于保持一个或两个 SCL 的母马（p<0.5）。形成三个 SCL 的马妊娠母马的孕酮浓度明显高于仅形成一个或两个 SCL 的母马（p<0.05）。在骡子妊娠中，形成不同数量的 SCL 的母马之间的孕酮或 eCG 浓度没有差异（p>0.05）。因此，eCG 刺激新的 SCL 的发育和现有的 CL 的功能。虽然这些作用在马妊娠的母马中表现得很明显，但骡子妊娠中 eCG 浓度较低会降低该激素对 CL 形成和功能的影响。
