Dmp1-CreERT2 targets osteocytes. (A) Experimental outline for reporter induction in Dmp1CreERT2 x TdTomato mice. (B) Representative images of induced TdTomato expression in osteocytes in the femur and (C, D) spine of corn oil- versus tamoxifen-treated Dmp1CreERT2 x TdTomato mice at low (10X, 20X, C) and high (40X, D) magnification. Black areas are bone, blue areas show extensive DAPI staining in the bone marrow. Scale bars = 10μm for 10X, 20X and 50μm for 40X. ;(E) Experimental outline for inducible deletion of ERα in osteocytes. (F) Images of RNAscope for Esr1 mRNA (encoding ERα) performed on spine bone sections from tamoxifen-treated Dmp1CreERT2 (Control) or ERαΔOcy mice. Scale bars = 50μm (G) Quantification of percentage of osteocytes positive for ERα observed from RNAscope (n = 6 per group [3 males (squares), 3 females (triangles)]). (H) Measurement of serum estradiol (E2) from cardiac blood (n = 15–16 per group). Boxes represent median and interquartile range and whiskers represent minimum and maximum values. Datasets were analyzed by unpaired t-test (G) or Mann-Whitney test (H).