Endocannabinoid inhibits LH release in OVX rats. (A) Effect on plasma LH levels of AEA (20 ng/2 μl), AM251 (200 ng/2 μl), AEA plus AM251, or 2 μl of saline for control group, injected i.c.v. in OVX rats. n = 7–9 animals per group. (B) Comparison of areas under the curve of LH secretion during 150 min after the injection of AEA. ***, P < 0.001 and **, P < 0.01 vs. control group; +++, P < 0.001 vs. AM251.