Role of low circulating FSH concentrations in controlling the interval to emergence of the subsequent follicular wave in cattle
Role of low circulating FSH concentrations in controlling the interval to emergence of the subsequent follicular wave in cattle
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DOI：
10.1530/rep.0.1240475
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发表时间：
2002-10-01
期刊：
影响因子：
3.8
通讯作者：
Kot, K
中科院分区：
文献类型：
--
作者：
Ginther, OJ;Bergfelt, DR;Kot, K
在对照（n = 7）和重组牛（rb）FSH处理（n = 7）的小母牛中，研究了卵泡波1（发情周期的第一波）和卵泡波2出现之间的间隔以及相关的FSH激增（激增1和激增2）之间的间隔。第1波两个最大卵泡直径偏差的预期开始时间定义为最大卵泡达到8.5 mm的那一天（第0天）。在对照母牛中，循环FSH浓度在第0天至第1.5天或第2.0天呈反比关系降低，雌二醇浓度升高。在接下来的3天里，FSH升高和雌二醇降低呈相反的关系。这个时间上的结果与雌二醇在这个时候对卵泡刺激素的全身负作用是一致的。给予rbFSH的剂量方案预计会导致rbFSH治疗组和对照组的FSH激增2之间的相似性。平均而言，rbfsh治疗组第2波和第2波的发生时间比对照组早约2天，两组之间FSH激增和卵泡波的特征相似（无显著差异）。这些结果支持了一个假设，即卵泡直径偏离后的低循环卵泡刺激素浓度控制了随后卵泡波出现的间隔。然而，在7只接受rbFSH治疗的母牛中，有1只在rbFSH的明显刺激下最大卵泡仅达到5.7 mm；因此，不能排除其他机制参与的可能性。
The intervals between emergence of follicular waves 1 (first wave of an oestrous cycle) and 2, and between the associated FSH surges (surges 1 and 2), were studied in control (n = 7) and recombinant bovine (rb)FSH-treated (n = 7) heifers. The expected start of the deviation in follicle diameter between the two largest follicles of wave I was defined as the day on which the largest follicle reached 8.5 mm (day 0). In the control heifers, circulating concentrations of FSH decreased and oestradiol increased between day 0 and day 1.5 or day 2.0 in a reciprocal relationship. The opposite reciprocal relationship between an FSH increase and an oestradiol decrease occurred during the next 3 days. This temporal result is consistent with a negative systemic effect of oestradiol on FSH at this time. rbFSH was administered in a dosage regimen that was expected to result in a similarity between FSH surge 2 in the rbFSH-treated group and surge 2 in the control group. On average, surge 2 and wave 2 occurred approximately 2 days earlier in the rbFSH-treated group than in the control group, and characteristics of the FSH surge and follicular wave were similar (no significant differences) between groups. These results support the hypothesis that low circulating FSH concentrations after the deviation in follicle diameter control the interval to emergence of the subsequent follicular wave. However, in one of seven rbFSH-treated heifers, the largest follicle from the apparent stimulation of rbFSH reached only 5.7 mm; therefore, the possibility of involvement of additional mechanisms cannot be dismissed.