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. 2010 Dec 29;152(2):595–606. doi: 10.1210/en.2010-0943

Fig. 4.

Fig. 4.

Central vasopressin administration reveals indiscriminate activation of kisspeptin neurons concomitant with gated activation of the GnRH system. Intracerebroventricular administration of AVP robustly activates kisspeptin-ir cells in the morning (ZT 1), whereas GnRH-ir cells remain inactive at this time point. In the afternoon (ZT 11), both kisspeptin-ir and GnRH-ir cells express high levels of FOS activation after saline or AVP injection. A (left panel), Low-power photomicrographs of GnRH-ir cells expressing FOS after i.c.v. saline (vehicle) or AVP administration at ZT 1 or ZT 11. A (right panel), Low-power photomicrographs of kisspeptin-ir cells in the AVPV expressing FOS after i.c.v. saline (vehicle) or AVP administration at ZT 1 or ZT 11. (B) Mean (±sem) percentage of GnRH-ir and kisspeptin-ir cells expressing FOS after saline or AVP at ZT 1 or ZT 11. C and D, Mean (±sem) total number of GnRH-ir and kisspeptin-ir cells after saline or AVP at ZT 1 (C) or ZT 11 (D). *, Significantly greater than the percentage of kisspeptin cells expressing FOS in hamsters treated with vehicle at ZT 1 (P < 0.05); †, significantly greater than females given the same pharmacological treatment at ZT 1 (P < 0.05).