Figure 1.

Experimental details. Time is depicted as days relative to the initiation of feed restriction or ad libitum feeding in controls, indicated by the horizontal bars. A, In experiment 1, vaginal lavage (Lav) was performed to assess estrous cyclicity in intact females receiving ad libitum feed or feed restriction; animals were euthanized for tissue collection the first day of diestrus that occurred after 14 days of feed restriction or ad libitum (control) feeding. B, Experiment 2 consisted of 3 subexperiments in which females were ovariectomized (OVX) and received a low, diestrus-like, estradiol implant (OVX + LowE) 10 days prior to receiving ad libitum feed or feed restriction. In experiment 2A, frequent blood samples were collected prior to (–1.5 to 0 hours) or following (72-73.5 hours) the onset of treatment, as indicated by the arrows. (Experiment 2B) Blood to evaluate Kp10-induced luteinizing hormone (LH) secretion or (experiment 2C) fixed neural tissue were collected 3 days following onset of ad libitum feed or feed restriction. C, In experiment 3, females were OVX and received a high, LH surge-inducing, estradiol implant (OVX + HighE) and blood and tissues were collected 2 days later.