Effects of hexarelin treatment on RER in (a) FVB mice, (d) RER in MKR mice, (g) total locomotor activity in FVB mice, and (j) total locomotor activity in MKR mice at days 0, 5, and 10 of treatment during dark phase (6:00 pm to 6:00 am) marked by shaded area in the graphs and light phase (6:00 am to 6:00 pm). AUC of RER during the (b) light and (c) dark phases of days 0, 5, and 10 of treatment in FVB mice. AUC of RER during the (e) light and (f) dark phases of days 0, 5, and 10 of treatment in MKR mice. AUC of locomotor activity during the (h) light and (i) dark phases of days 0, 5, and 10 of treatment in FVB mice. AUC of locomotor activity during the (k) light and (l) dark phases of days 0, 5, and 10 of treatment in MKR mice. Data are expressed as mean ± SEM (n = 4 per group). *P < 0.05 vs MKR saline group; ##P < 0.01 vs FVB saline group at day 0.