Our study confirms a previous finding that exogenous PTHrP promotes fracture repair by increasing callus formation and accelerating cell transformation [28], while endogenous PTHrP deficiency might result in osteoporosis and impaired bone formation in mice [20,29], which implies a potential application of exogenous PTHrP to repair bone damage and accelerate fracture healing clinically. Here, PTHLH is linked to osteoporosis.