Adipoq-Cre, PPARγfl/fl, adiponectin–/–, and leptin–/– mice were purchased from The Jackson Laboratory. FF mice were generated by mating homozygous Lox-stop-Lox-ROSA-DTA mice (7 (link)) to those expressing Adipoq-Cre. Adipocyte-specific PPARγ deletion mice were generated by mating PPARγfl/fl mice with Adipoq-Cre (PPAR ADQ). Lox-stop-Lox-ROSA-DTA mice and PPARγfl/fl mice were used as control mice of FF mice and PPAR ADQ mice, respectively. C57BL/6 and Leptin+/– mice were used as control mice of adiponectin–/– and leptin–/– mice, respectively. Both FF and PPAR ADQ mice could not survive at room temperature after birth because of lack of BAT, so they were housed at thermoneutral condition (30°C) till weaning age (3 weeks old). All other mice were kept at 22°C on a 12-hour light/12-hour dark cycle. Although no sex differences existed in phenotype, female mice were exclusively used. Mice used in experiments were 8–16 weeks old.
For HFD-feeding studies, mice were fed with chow diet until age 8 weeks and thereafter were randomized into groups that were fed either chow diet or HFD (Research Diets Inc., catalog D12492) for 3 months. Metformin was purchased from MP Biomedicals and dissolved in mouse drinking water (2 g/L) (7 (link)). Fresh drinking water with Metformin was changed daily for 2 months.
For HFD-feeding studies, mice were fed with chow diet until age 8 weeks and thereafter were randomized into groups that were fed either chow diet or HFD (Research Diets Inc., catalog D12492) for 3 months. Metformin was purchased from MP Biomedicals and dissolved in mouse drinking water (2 g/L) (7 (link)). Fresh drinking water with Metformin was changed daily for 2 months.