Body weight (A) and weight gain (B) of male rats, in experiment I, treated with oxytocin (filled circles) or NaCl(open squares). Values are mean ± SD. Statistical evaluation was performed by a two-way ANOVA. (A) Treatment: F1,100= 1.32, p = 0.28, interaction (age × treatment):F1,100 = 4.37, p = 0.0001; (B) treatment:F1,90 = 9.27, p = 0.012, interaction (age × treatment): F1,90 = 1.31, p = 0.24. Significant(*p < 0.05) difference between oxytocin- and saline-treated rats, assessed by a t test.