Osteoblast specific Y1 deletion is protective against high fat diet induced glucose intolerance and insulin resistance. Y1F3.6Cre mice fed a high fat diet are not different in terms of bodyweight compared to controls (A). The two groups also similar increases in fat mass (B), Glucose (C) and insulin levels (D). While overall glucose tolerance has been reduced under high fat conditions in both groups, the effect is much less severe in the Y1F3.6Cre mice, which show significant improved glucose tolerance compared to controls (E) and AUC (F). The rise in insulin levels during GTT were also lower in Y1F3.6Cre mice (G) also reflected in AUC (H). Importantly, insulin action was strongly improved in the Y1F3.6Cre mice fed a high fat diet as shown by the significantly reduced glucose levels during insulin tolerance test (I) and AUC (J). Data are means ± SEM of 5–12 mice per group.* = p < 0.05, ** = p < 0.01, *** = p < 0.001 versus control or as indicated.