Mice were provided food and water ad libitum and were maintained on a 12 hour light/dark cycle. The mice were fed isocaloric diets containing 10 percent fat/70 percent carbohydrate (D12450B) or 60 percent fat/20 percent carbohydrate (D12492) from Research Diets Inc. (New Brunswick, NJ). The protein content of each of these diets is depleted of iso-flavones, which have major endocrine impacts, and the fat is derived from lard. Diets were administered for 6, 11 or 36 weeks post-weaning, as indicated (Figure 1A). The initial Cyp1b1-ko founders (on C57BL/6 background) were obtained from Dr. Frank Gonzalez [23]. The original colony (1997) was backcrossed to Jackson C57BL/6j (WT) mice through 10 generations, but subsequently inbred for several years. This colony provided consistent obesity responses over the generations used in these studies, with the exception of blood glucose analyses. Treatments were compared between littermates from multiple litters over more than 12 months. Comprehensive data was collected for food consumption (Figure S1A) and body weight (BW) gain over this period of time (Figure 1B). A second phase of the study was started when an
