Robinson R S, Hammond A J, Hunter M G, Mann G E
Division of Animal Physiology, University of Nottingham, Sutton Bonington Campus, Loughborough, LEICS LE12 5RD, UK.
Domest Anim Endocrinol. 2005 Apr;28(3):285-95. doi: 10.1016/j.domaniend.2004.10.003.
A delayed rise in post-ovulatory progesterone is associated with poor embryo development in the cow, although the underlying cause of this aberrant luteal function is poorly understood. The objective of this study was to develop a novel model, in which a delayed progesterone rise could be induced by manipulating the dynamics of the follicular phase. Luteolysis was induced in 20 dairy cows in the presence of either a larger follicle > 10 mm (LF, n = 11) or a smaller follicle < 10 mm (SF, n = 9) and transrectal ultrasonography was performed to determine follicle and CL growth and timing of ovulation. Plasma progesterone and oestradiol were analysed 3x daily. Cows were slaughtered on either day 4 (n = 4 per group) or day 7 (SF, n = 5; LF, n = 7) after ovulation. The pre-ovulatory follicle was larger in the LF group than the SF group at luteolysis (13.5 +/- 0.4 mm versus 6.7 +/- 0.7 mm, P < 0.001) and ovulation (16.7 +/- 0.3 mm versus 13.6 +/- 0.6 mm, P < 0.001). The LF group experienced a shorter follicular phase and ovulated 36 h earlier than the SF group (P < 0.001). At luteolysis, plasma oestradiol concentrations were greater in the LF group (P < 0.001), although peak concentrations were not different (P > 0.05). Moreover, higher progesterone concentrations were observed in the LF group during the early luteal phase (P < 0.05). Luteal weights were positively correlated with plasma progesterone concentrations on day 5 (P < 0.05) but not day 8. In conclusion, a model has been developed which has shown that the dynamics of follicle development during the pre-ovulatory period is an important determinant of subsequent CL development and function.
排卵后孕酮的延迟升高与奶牛胚胎发育不良有关，尽管这种异常黄体功能的根本原因尚不清楚。本研究的目的是建立一种新型模型，通过操纵卵泡期的动态变化来诱导孕酮延迟升高。在20头奶牛中诱导黄体溶解，其中11头存在大于10毫米的较大卵泡（LF组），9头存在小于10毫米的较小卵泡（SF组），并通过经直肠超声检查来确定卵泡和黄体的生长情况以及排卵时间。每天分析3次血浆孕酮和雌二醇水平。在排卵后第4天（每组4头）或第7天（SF组5头；LF组7头）屠宰奶牛。在黄体溶解时，LF组的排卵前卵泡大于SF组（13.5±0.4毫米对6.7±0.7毫米，P<0.001），排卵时也是如此（16.7±0.3毫米对13.6±0.6毫米，P<0.001）。LF组的卵泡期较短，比SF组提前36小时排卵（P<0.001）。在黄体溶解时，LF组的血浆雌二醇浓度更高（P<0.001），尽管峰值浓度没有差异（P>0.05）。此外，在黄体早期，LF组的孕酮浓度更高（P<0.05）。黄体重量与第5天的血浆孕酮浓度呈正相关（P<0.05），但与第8天无关。总之，已建立了一种模型，该模型表明排卵前期卵泡发育的动态变化是随后黄体发育和功能的重要决定因素。
