As for preclinical studies, very limited data are available on the recovery of bone turnover after withdrawal of bisphosphonate therapy(9) and changes in areal BMD following discontinuation of PTH treatment in rats.(10) Using an osteoporotic rat model, we report a series of bone structural and material properties related to changes in bone turnover and bone mass during withdrawal of antiresorptive and anabolic agents commonly used for treatment of osteoporosis. This evidence concerns the gene PTH and osteoporosis.