Two effects of estradiol that normally contribute to the control of tonic LH secretion in the ewe.
Two effects of estradiol that normally contribute to the control of tonic LH secretion in the ewe.
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DOI：
10.1095/biolreprod23.2.415
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发表时间：
1980-09
影响因子：
3.6
通讯作者：
R. Goodman;S. Legan;K. Ryan;D. Foster;F. Karsch
中科院分区：
文献类型：
--
作者：
R. Goodman;S. Legan;K. Ryan;D. Foster;F. Karsch
当在没有卵巢的情况下通过在硅橡胶植入物中施用雌二醇和黄体酮来再现动情周期的类固醇环境时，观察到雌二醇对母羊的强直性 LH 分泌的两种影响。在与卵泡期相对应的模型中，即循环黄体酮急剧下降后，揭示了雌二醇的一种效应。在这些条件下，雌二醇降低了黄体酮停药引起的强直 LH 分泌增加的幅度。重要的是，基础雌二醇水平在这方面完全有效；高于基础浓度的增量不会对 LU 产生进一步的显着抑制。雌二醇的第二个作用是在类似于黄体期的条件下发现的，即血清孕酮逐渐增加。雌二醇极大地增强了所有剂量的黄体酮抑制 LH 的能力。同样，在这方面，较高的雌二醇浓度似乎并不比基础浓度更有效。
Two effects of estradiol on tonic LH secretion in the ewe were observed when the steroidal milieu of the estrous cycle was reproduced in the absence of the ovaries by the administration of estradiol and progesterone in Silastic implants. One effect of estradiol was revealed in a model corresponding to the follicular phase, namely following a precipitous decrease in circulating progesterone. Under these conditions, estradiol diminished the magnitude of the increase in tonic LH secretion initiated by progesterone withdrawal. Importantly, basal estradiol levels were fully effective in this regard; increments above basal concentrations produced no further significant inhibition of LU. The second effect of estradiol was revealed under conditions resembling the luteal phase, namely in the presence of graded increases in serum progesterone. Estradiol greatly enhanced the ability of all doses of progesterone to suppress LH. Again, higher estradiol concentrations did not appear to be more effective in this regard than basal concentrations.