The GnRH antagonist, acyline, blocks the effects of kisspeptin-54 on plasma LH in the mouse. Kisspeptin-54 (50 pmol) and vehicle were administered into the lateral ventricle. Pretreatment with the GnRH antagonist, acyline (50 μg) or saline was given sc. *, P < 0.001 saline + kisspeptin-54 vs. all other treatments. [Modified with permission from Gottsch et al., 2004 (72) © The Endocrine Society].