a, b, Day of pubertal maturation as measured by the preputial separation in male mice (a) (N values: 4 (WT), 14 (for Mc3r+/−) and 9 (Mc3r−/−); Kruskal–Wallis test, P = 0.015), and first oestrous cycle in female mice (b) (N values: 4 (WT), 15 (Mc3r+/−) and 7 (Mc3r−/−); Kruskal–Wallis test, P = 0.280). Mean ± s.e.m. is shown. c, Quantification of the length of the oestrous cycle in WT (N values: 19 (fasted) and 38 (fed)) and Mc3r−/− mice (N values: 14 (fasted) and 19 (fed)) in either ad libitum fed and fasted conditions. Mean ± s.e.m. is shown (two-way ANOVA with Bonferroni post-hoc; NS, not significant; *P ≤ 0.05; ****P ≤ 0.0001). d, Number of oestrous cycles per 15 days in WT and Mc3r−/− mice in ad libitum fed and fasted conditions. Mean ± s.e.m. is shown (two-way ANOVA with Bonferroni post-hoc; *P ≤ 0.05; ****P ≤ 0.0001).