(a) Quantification of glucose consumption and lactate secretion (PC, COB: n=6, GCH: n=5 biologically independent samples), glycolytic rate (n=3 biologically independent samples), oxygen consumption (PC, COB: n=7, GCH: n=5 biologically independent samples), glucose oxidation (n=3 biologically independent samples) and palmitate oxidation (n=3 biologically independent samples) in periosteal cells (PC), growth plate-derived chondrocytes (GCH) and calvarial osteoblasts (COB). (b) Analysis of adjacent histological sections of a growth plate and fracture callus (PFD7) by Safranin O staining (cartilage) or immunofluorescence for CPT1a or GLUT1 (representative images of 3 mice). Scale bars, 100μm. b: bone, c: cartilage. Dotted white lines delineate cartilage areas. (c) Histological visualization and quantification of early chondrogenic (SOX9+) and osteogenic (COL1+) cells in the callus of fractures (PFD7) transplanted with CAG-DsRed+ skeletal stem cells (SSC) transduced with shCPT1a or shSCR (n=3 mice). Scale bars, 50μm. (d) Measurement of oxidation of extracellularly added palmitate by periosteal cells in control medium or at different times in SD medium (n=3 biologically independent samples). (e) Quantification of FAO-linked OCR in periosteal cells in control medium or at different times in SD medium (3h: n=2, other timepoints: n=3 biologically independent samples). (f) Quantification of FAO-linked OCR in periosteal cells, transduced with shSOX9 or shSCR, in control medium or at different times in SD medium (shSCR 12h, shSOX9 control, shSOX9 3h: n=5, all others: n=6 biologically independent samples). (g) Quantification of FAO-linked OCR in GCH transduced with shSOX9 or shSCR (n=5 biologically independent samples). (h) Quantification of palmitate oxidation in GCH transduced with shSOX9 or shSCR, and in COB transduced with a lentiviral vector encoding SOX9 (SOX9 overexpression; SOX9OE) or an empty vector (EV) (n=4 biologically independent samples). Mean ± s.e.m. One-way ANOVA (a,d,e) or two-way ANOVA (f) with Bonferroni post-hoc test, two-tailed Student’s t-test (c,g,h).