Fig. 13.

Male-female sex differences in the effects of transgenic deletion of the melanocortin 4 receptor gene (Mc4r^−/−) on eating and weight gain in mice. Male and female Mc4r^−/− and wild-type (WT) mice were fed a low-fat diet (LFD) from weaning to age 12 wk and then a high-fat diet (HFD) until week 22. Data are means of food intakes (kJ/day) ± SE and were measured for low-fat diet (LFD) from age 7 to 12 wk (top) and a high-fat diet (HFD) from age 12 to 22 wk (middle). Bottom: body weight gains (g, means ± SE) between week 7, when all mice had similar weights, to week 22. Note that female Mc4r^−/− apparently increased food intake relative to female WT mice more than male Mc4r^−/− mice on both diets and gained more weight than males (although the authors reported significant main effects of sex in their ANOVA, they did not test these relative differences for significance). Republished with permission of the Endocrine Society, from Endocrinology, Gregory M. Sutton, James L. Trevaskis, Matthew W. Hulver, Ryan P. McMillan, Nathan J. Markward, M. Josphine Babin, Emily A. Meyer, and Andrew A. Butler, 147: 2186–2006, 2006; permission conveyed through Copyright Clearance Center, Inc.; from Sutton et al. (712).