In vivo effects of administered ghrelin in wild-type and GHSR-A203E littermates. (A) Ghrelin [0 (saline), 0.1, and 1 mg/kg s.c.)-induced 2 h food intake in 25-week-old male mice (n = 7–10). (B–C) Ghrelin (2 mg/kg s.c.)-induced (B) 2 h food intake and (C) RER (2 h after ghrelin administration) in 9–12-week-old male mice (n = 6–7). (D) Ghrelin (0.5 mg/kg i.p.)-induced GH secretion in 7-week-old mice (n = 3–4). (E) GHRH (0.5 mg/kg i.p.)-induced GH secretion in 10-week-old mice (n = 7). (F) Plasma IGF-1 (n = 6–8) and (G) pituitary GH content (n = 5–8) in 66-week-old mice. Data were analyzed by (A) a 2-way ANOVA followed by a Tukey post hoc analysis, (B–E) a 2-way repeated measures ANOVA followed by a Sidak's multiple comparison post hoc analysis, or (F–G) an unpaired Student's t-test. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗∗P < 0.0001, #0.05 ≤ P < 0.1, and n.s. = non-significant.