奶牛生殖激素的分析 Ⅴ、发情周期和怀孕期间外周血浆17β一雌二醇的变化

采用放射免疫分析法测定了黑白花奶牛在发情周期中和怀孕期间外周血浆17β一雌二醇的变化.结果表明,在发情周期中17β一雌二醇出现三次分泌高峰;第一次是在发情前一天(8.9±0.5pg/ml);第二次在发情周期的第4—7天;第三次在第10—15天。后两次的峰值均比第一次较低.已怀孕的母牛出现第二次和第三次高峰的时间基本与发情周期的相同,但第三次的持续时间较长,一直维持到第22天.怀孕母牛的这一分泌特点尚未见到报道.此后,怀孕母牛外周血浆的17β一雌二醇一直处于较低水平,但从怀孕第五个月又开始逐月升高,至怀孕9个月时达到最高峰(132.5±24.5pg/ml).

Analysis of Reproductive Hormones in Dairy Cow V.Profile of 17β—Oestradiol in the Peripheral Blood Plasma During Oestrous Cycle and Pregnancy

The profile of oestradiol-17β in the peripheral blood plasma of Holstein-Friesian cows during oestrous cycle and pregnancy was investigated by RIA.The results show three oestradiol-17β peaks during the cycle,the first on the day just before oestus,the second and third on day 4-7 and 10-15 respectively and are lower than the first one. In pregnant cows,the second and third oestradiol peaks are similar to those of cyclic cows in the time of appearence,however,the third peak lasts longer,until day 22 after insemination.Then the value remains low,fluctures only slightly.It rises again in the fifth month,and culminates in a hightest peak(132.5±24.5pg/ml) in the ninth month.