Figure 4:

An example showing that infusion of letrozole (100nM, light grey bars) into the median eminence inhibits the EB-induced as well as spontaneous release of GnRH (black line with filled circle) and E₂ (red line with filled square). EB challenge (100 nM, dark grey bars) was first infused for 20 min with vehicle, subsequently letrozole (100 nM, light grey bars) was continuously infused for 100 min, during which EB (100 nM) infusion was added for 20 min (60–80 min after the initiation of letrozole infusion), and finally letrozole (100 nM) alone was infused for 80 min. Note that control EB infusion stimulates release of GnRH and E₂, whereas EB infusion in the presence of letrozole fails stimulating release of GnRH or E₂. Letrozole infusion alone also blocks spontaneous GnRH pulses (A). From Kenealy et al., 2013. Permission pending.