Plasma glucose (A and F), ACTH (B and G), cortisol (C and H), noradrenaline (D and I) and adrenaline (E and J) concentrations in low (•) and high (○) BW pigs prior to and following insulin administration (0.5 IU (kg body weight)−1; i.v.) at time 0 min (arrows) at 3 (A-E) and 12 (F-J) months of age. At 3 months of age, cortisol concentrations during insulin challenge in low BW pigs were significantly (P < 0.005) greater than in high BW pigs (* 2-way ANOVA). At 12 months of age, noradrenaline concentrations during insulin challenge in low BW pigs were significantly (P < 0.05) lower than in high BW pigs (* 2-way ANOVA).