Effect of fat transplantation on insulin sensitivity of A-ZIP/F-1 mice. (a) Female mice (n = 3–9/group; transplanted with 900 mg of adipose tissue 5 weeks earlier) were fasted for 8 hours, then glucose (2 mg/g, intraperitoneally) was injected and blood glucose was measured at the indicated times. *P < 0.001 WT versus sham; ⁺P < 0.02 transplanted versus sham. (b) Male mice (n = 3 to 9/group; transplanted with 900 mg of adipose tissue 8 weeks earlier) were fasted for 15–21 hours and then injected with insulin (0.75 mU/g), and blood glucose was measured at the indicated times. *P < 0.03 transplanted versus sham. (c) Tissue uptake of [¹⁴C]2-deoxyglucose in mice (n = 3/group, a subset of those in b) was measured 45 minutes after a single intraperitoneal injection. Muscle uptake was measured in gastrocnemius muscle and in either epididymal (WT) or transplanted adipose tissue. ⁺P = 0.07, sham A-ZIP/F-1 versus wild-type; *P = 0.004, transplanted versus sham A-ZIP/F-1. dpm, disintegrations per minute. (d) Female mice (n = 4/group; transplanted with 900 mg of adipose tissue 6 weeks earlier) were fasted for 13 hours, then [³H]2-deoxyglucose (2-DG) uptake into extensor digitorum longus muscle in the absence (basal) or presence of insulin was measured. *P < 0.001 versus basal WT; **P = 0.01 versus insulin-treated WT; ⁺P = 0.01 versus insulin-treated sham A-ZIP/F-1.