Leipheimer R E, Bona-Gallo A, Gallo R V
Endocrinology. 1986 May;118(5):2083-90. doi: 10.1210/endo-118-5-2083.
The aim of this study was to examine the regulation of basal pulsatile LH release by ovarian estradiol (E2) and progesterone (P) during the interval between the mornings of proestrus and estrus in the rat estrous cycle. Pulsatile LH release was studied in six groups of rats bled continuously through jugular venous cannulae between 0930-1230 h at a rate of 50 microliter whole blood/5 min: 1) bled on proestrus; 2) sham ovariectomy (OVX) at 0900-1000 h on proestrus and bled on estrus; 3-6) OVX at 0900-1000 h on proestrus, implanted with either empty or E2-, P-, or E2- plus P-containing Silastic capsules, and bled 24 h after OVX. In our colony, plasma E2 levels peaked at 1300 h, remained high through 1730 h, and then declined. Plasma P values increased between 1300 and 1730 h, peaked at 2000 h, and were rapidly declining by 2400 h. To reproduce the magnitude as well as the temporal pattern for these changes in plasma E2 and P levels, E2 capsules were inserted at the time of OVX on proestrus and removed at 1830 h. P capsules were inserted at 1400 h and removed at 2300 h. Groups of ovariectomized or sham-ovariectomized control animals had empty capsules implanted and removed at comparable times. Capsules producing basal E2 and P levels were not inserted after the removal of the original implant, since mean blood LH levels, pulse amplitude, and frequency were the same in rats sham ovariectomized or ovariectomized at 1830 h on proestrus and bled the next morning between 0930-1230 h. Mean blood LH levels decreased between the mornings of proestrus and estrus due to a reduction in LH pulse frequency as pulse amplitude remained stable. OVX at 0900-1000 h on proestrus increased mean blood LH levels 2.5-fold compared to values on estrus due to increases in both LH pulse frequency and amplitude. Restoration of physiological proestrous levels of only E2 returned LH pulse frequency to estrous values, but did not significantly affect LH pulse amplitude. P alone also had no significant effect on LH pulse amplitude, but slightly reduced pulse frequency, although, unlike E2, not to values seen on estrus. Replacing both E2 and P returned LH pulse amplitude to estrous levels and reduced LH pulse frequency.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究的目的是在大鼠发情周期中，检查动情前期早晨至发情期早晨这段时间内，卵巢雌二醇（E2）和孕酮（P）对基础促黄体生成素（LH）脉冲式释放的调节作用。通过颈静脉插管，以50微升全血/5分钟的速率，在0930 - 1230时对六组大鼠进行连续采血，研究LH的脉冲式释放：1）在动情前期采血；2）在动情前期0900 - 1000时进行假卵巢切除（OVX），并在发情期采血；3 - 6）在动情前期0900 - 1000时进行OVX，植入空的或含E2、P或E2加P的硅橡胶胶囊，并在OVX后24小时采血。在我们的实验群体中，血浆E2水平在1300时达到峰值，一直保持高水平至1730时，然后下降。血浆P值在1300至1730时升高，在2000时达到峰值，并在2400时迅速下降。为了重现血浆E2和P水平这些变化的幅度和时间模式，在动情前期OVX时插入E2胶囊，并在1830时取出。P胶囊在1400时插入，在2300时取出。去卵巢或假去卵巢的对照组动物植入并在相应时间取出空胶囊。在取出原始植入物后，不再插入产生基础E2和P水平的胶囊，因为在动情前期1830时进行假卵巢切除或去卵巢并于次日早晨0930 - 1230时采血的大鼠中，平均血LH水平、脉冲幅度和频率相同。由于LH脉冲频率降低而脉冲幅度保持稳定，动情前期早晨至发情期早晨的平均血LH水平下降。由于LH脉冲频率和幅度均增加，动情前期0900 - 1000时进行OVX使平均血LH水平比发情期的值增加了2.5倍。仅恢复生理动情前期水平的E2可使LH脉冲频率恢复到发情期的值，但对LH脉冲幅度无显著影响。单独使用P对LH脉冲幅度也无显著影响，但略微降低了脉冲频率，不过与E2不同，未降至发情期所见的值。同时补充E2和P可使LH脉冲幅度恢复到发情期水平，并降低LH脉冲频率。（摘要截选至400字）
