1-Alpha-OH-cholecalciferol (1-alpha-OH-D3) and optimal calcium intake in calcium deficiency osteoporosis mediated by parathyroid activity morphologic and biochemical changes in adult male rats.

By feeding adult male rats a calcium deficient diet for a period of 6 weeks osteoporosis can be induced with respect to significant changes in mass, turnover, chemical composition, and morphology of bone and parathyroid glands. When subsequently treating the osteoporotic rats with a combination of 1-alpha-OH-cholecalciferol (1-alpha-OH-D3) and optimal calcium intake osteoporosis as well as morphologic changes of parathyroids can be almost totally reversed as soon as after 2 weeks and completely after 4 and 6 weeks. Notwithstanding the change to an optimal calcium intake seems to be more important in normalizing the osteoporotic skeleton resulting from calcium deficiency than is the ingestion of 1-alpha-OH-D3, which may per se induce new bone formation.