FIG. 2.

Insulin induces a transient hypothalamic ROS increase, which is required for food intake inhibition. A: Insulin effect on ROS production. After intracerebroventricular injection of insulin (0.4 μU) or vehicle, ROS levels were assessed by oxidation of H₂DCFDA probe in the hypothalamus at different times (n = 5 mice per group). Dichlorofluorescein (DCF) fluorescence is expressed in arbitrary units per microgram of protein. B and C: Effect of Trolox on insulin-induced ROS production and food intake inhibition. Trolox (0.1 mmol/l) was intracerebroventricularly injected 30 min before insulin (0.4 μU). ROS levels were assessed in the hypothalamus 15 min after injections (n = 5 mice per group) (B). Food intake was assessed 12 h after food presentation (n = 5–10 mice per group) (C). Data are the means ± SE. *P < 0.05, **P < 0.01, ***P < 0.001 vs. vehicle- or insulin-injected group.