Murphy L L, Tyrey L
Neuroendocrinology. 1986;43(4):471-5. doi: 10.1159/000124569.
The predominant psychoactive constituent of marijuana, delta 9-tetrahydrocannabinol (THC), blocks the preovulatory luteinizing hormone (LH) surge and ovulation in rats treated with THC (10 mg/kg body weight) during the early afternoon of proestrus. When THC-blocked proestrous rats were subjected to unilateral electrochemical stimulation (100 microA anodal DC for 45 s) in the medial preoptic area (mPOA), serum LH was significantly elevated at 30, 60 and 90 min after stimulation in comparison with LH levels measured in sham-stimulated control animals at those times. The induced LH release was sufficient to elicit ovulatory responses comparable to the spontaneous ovulations observed in control rats treated only with the drug vehicle. These results are consistent with the hypothesis that THC inhibits gonadotropin secretion by action within the central nervous system, but demonstrate that the central inhibitory effect of THC does not prevent the release of LH-releasing hormone (LHRH) when the LHRH neurosecretory units are activated by brain stimulation. Thus, the antiovulatory effect of THC appears to result from an inhibition of LH secretion which does not involve the direct blockade of LHRH release.
大麻的主要精神活性成分Δ⁹ - 四氢大麻酚（THC），在动情前期下午早些时候用THC（10毫克/千克体重）处理的大鼠中，会阻断排卵前促黄体生成素（LH）的激增和排卵。当对THC阻断的动情前期大鼠在内侧视前区（mPOA）进行单侧电化学刺激（100微安阳极直流电，持续45秒）时，与假刺激对照动物在相应时间测量的LH水平相比，刺激后30、60和90分钟血清LH显著升高。诱导的LH释放足以引发与仅用药物载体处理的对照大鼠中观察到的自发排卵相当的排卵反应。这些结果与以下假设一致：THC通过在中枢神经系统内起作用来抑制促性腺激素分泌，但表明当LHRH神经分泌单位通过脑刺激被激活时，THC的中枢抑制作用并不阻止促黄体生成素释放激素（LHRH）的释放。因此，THC的抗排卵作用似乎是由对LH分泌的抑制导致的，这种抑制并不涉及对LHRH释放的直接阻断。
