Changes in body weight, serum leptin, serum luteinising hormone (LH), and arcuate nucleus (ARC) Kiss1 mRNA levels in response to the 48-h fast. (A) Change in body weight was calculated as the total % change in body weight over the 48 h period; CTRL, control; F, fasted; F + Leptin, fasted with 500 ng/g of body weight leptin treatment via osmotic minipump; F + High Leptin, fasted with twice daily injections of 3 μg/g of body weight leptin. Serum leptin was measured by radioimmunoassay (RIA) and the dotted line denotes the lower threshold of detectability for the leptin RIA. (B) Serum LH was also measured by RIA. Kiss1 mRNA was measured by real-time polymerase chain reaction from microdissected ARC samples. Columns with different letters are significantly different (P < 0.05).