(a) Growth curve of H3^+/+ and H3^–/– male mice (n = 9 or 10, **P < 0.01). H3^+/+ mice are indicated by squares and H3^–/– mice by triangles. (b) Growth curve of H3^+/+ and H3^–/– female mice (n = 7 or 8, **P < 0.01). H3^+/+ mice are indicated by squares and H3^–/– mice by triangles. (c) Food intake of H3^+/+ and H3^–/– mice. Shown is the 24-hour food consumption of 21- to 26-week-old male and 19- to 21-week-old female mice fed ad libitum (n = 7–9, *P < 0.05, **P < 0.01). H3^+/+ mice are indicated by white bars and H3^–/– mice by black bars. (d) Growth curve and daily food intake of H3^+/+ and H3^–/– male mice (n = 12–16, *P < 0.05). H3^+/+ mice are indicated by squares and white bars and H3^–/– mice by triangles and black bars.