Frias J, Puertas A, Ruiz E, Ortega E
Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Faculty of Medicine, University of Granada, Spain.
Neurochem Res. 1997 Feb;22(2):171-4. doi: 10.1023/a:1027363523342.
We determined the dose-response relationship and examined the time-related effect of CRF (corticotropin releasing factor) injected directly into the Median Eminence (ME) on LH secretion in conscious intact and castrated male rats. Doses of 0.25, 0.75, 1, and 1.5 nmol CRF dissolved in 1 microl of saline (or saline only in the controls) were injected into the ME and blood samples collected 30, 60, 90, and 120 min postinjection to determine by RIA serum LH. CRF at doses of 0.75, 1 and 1.5 nmol significantly decreased serum LH in castrated and intact animals. The lower dose of CRF did not decrease LH in the two groups studied. The results suggest that in males as in females, CRF inhibits by itself LH secretion, at least in part, by a central action in the ME; the inhibitory effect of CRF on LH is similar in castrated and intact males; the dose of 0.25 nmoles of CRF was ineffective in decreasing LH and finally that CRF at ME levels may participate in a variety of stress-related responses, including reproduction inhibition, through LH suppression.
我们测定了剂量反应关系，并研究了直接注入正中隆起（ME）的促肾上腺皮质激素释放因子（CRF）对清醒完整和去势雄性大鼠促黄体生成素（LH）分泌的时间相关效应。将溶解于1微升生理盐水的0.25、0.75、1和1.5纳摩尔CRF（对照组仅注射生理盐水）注入ME，并在注射后30、60、90和120分钟采集血样，通过放射免疫分析法（RIA）测定血清LH。0.75、1和1.5纳摩尔剂量的CRF显著降低了去势和完整动物的血清LH。较低剂量的CRF在研究的两组中并未降低LH。结果表明，与雌性一样，在雄性中CRF至少部分通过在ME中的中枢作用自身抑制LH分泌；CRF对LH的抑制作用在去势和完整雄性中相似；0.25纳摩尔的CRF剂量在降低LH方面无效，最后表明ME水平的CRF可能通过抑制LH参与包括生殖抑制在内的各种应激相关反应。
