Similarly, mast cells were not detected in bone marrow following ovariectomy, oophorectomy, high-fat feeding, simulated hyperparathyroidism (continuous infusion of parathyroid hormone (PTH)), simulated microgravity (hindlimb unloading), high-dose irradiation, polyethylene particle-induced systemic bone loss, spinal cord injury-induced systemic bone loss, temperature stress, or hormones, drugs, and genetic manipulations that influence bone metabolism. The gene discussed is PTH; the disease is hyperparathyroidism.