Upregulation of Socs3 in leptin receptor neurons does not result in obesity but rather in a subtle lean phenotype. A: Body weight of LepRb-Socs3-OE on chow diet at indicated ages. Mutants became slightly leaner at 7 weeks of age (controls n = 16–44, mutants n = 10–27). B: Length of LepRb-Socs3-OE at 5 weeks of age (controls n = 14, mutants n = 8) and 12 weeks of age (controls n = 12, mutants n = 7) was identical. C: Analysis of lean mass and fat mass by DEXA at 10 weeks of age (controls n = 12, mutants n = 8). D: The 12-week-old LepRb-Socs3-OE mutants showed significantly decreased interscapular, retroperitoneal, and total white adipose tissue on a chow diet (controls n = 11, mutants n = 8). E: Plasma leptin levels under fed conditions for LepRb-Socs3-OE mice at 12 weeks of age (controls n = 9, mutants n = 5). F: 24-h food intake of LepRb-Socs3-OE mice at 6–8 weeks of age was reduced (controls n = 6, mutants n = 6). G: The 6- to 8-week-old LepRb-Socs3-OE and control mice were injected intraperitoneally with saline twice daily for 3 consecutive days and leptin (2.5 mg/kg) twice on the fourth day. 24-h food intake after leptin treatment was reported as a ratio of food intake after saline treatment (controls n = 6, mutants n = 6). Data represent mean ± SEM. WAT, white adipose tissue. *P < 0.05, between controls and mutants as determined by 2-way ANOVA.