(A, B) Body weight curves of wild-type male (A) and female (B) mice on a high fat diet were significantly higher than those of wild-type mice on a low fat diet (p<0.0005, both sexes). CAG/orexin mice did not differ significantly under low fat and high fat dietary conditions (p= 0.51 male; p=0.13 female).
(C, D) Body weight curves of OX1R−/− male (C) and female (D) mice on a high fat diet were significantly higher than those of OX1R−/− mice on a low fat diet (p<0.0001 in male; p<0.01 in female). OX1R−/−; CAG/orexin male mice did not differ significantly between low fat and high fat dietary conditions (p=0.21). The body weights of OX1R−/−; CAG/orexin female mice on a high fat diet were significantly less than those of OX1R−/− mice on a high fat diet (p<0.01), in spite of no body weight difference between OX1R−/−; CAG/orexin female mice and OX1R−/− female mice on a low fat diet (p=0.50).
(E,F) The body weight growths of OX2R−/− male (E) and female (F) mice on a high fat diet were significantly higher than those of OX2R−/− mice on a low fat diet (p<0.0001 in male; p<0.005 in female). Likewise, OX2R−/−; CAG/orexin male (E) and female (F) mice showed significant weight gain on a high fat diet compared to those on a low fat diet (p<0.0005 in male; p<0.001).
Body weights of mice measured weekly from the age of 3 weeks to 30 weeks. A high fat diet started at the age of 8 weeks (dotted line). The numbers of mice are 10–14 mice per group. * indicates significant difference between different diet condition for each genotypic group according to post-hoc analysis at each time point. Significant difference in (F) for OX2R−/− mice and OX2R−/−; CAG/orexin are indicated by one asterisk. Data are expressed as means ± SEM.