Effects of 12 days of sc leptin infusion on longitudinal bone growth (A), indices of bone formation consisting of osteoblast perimeter (B), mineralizing perimeter (C), mineral apposition rate (D), bone formation rate (E), and serum osteocalcin (F), and indices of bone resorption consisting of osteoclast perimeter (G) and serum CTx-1 (H) in female ob/ob mice (n=8/group). Representative photomicrographs illustrating differences in fluorochrome labeling in ob/ob mice treated with vehicle (I) and ob/ob mice infused with 12 ng/h leptin (J). Effects of leptin on trabecular thickness, an index of bone microarchitecture, is shown in K. Data are mean ± SE. aDifferent from vehicle-treated ob/ob mice (ob/ob 0), P<0.05. WT is shown as a reference group.