[Influence of active vitamine D3 on bones (author's transl)]

Influence of 1 alpha-OH-D3, an active vitamine D supplement, on bone cells was studied, histologically and electro-microscopically observing the vitamine D objective bone cell after treatment with the drug in a dose of 50 microgram/kg/day. Light-microscopic findings revealed that osteogenesis gradually became dominant after transient osteoporosis, leading to a disproportional state of the bone remodelling. In electromicroscopy, no morphological changes were observed, though the number of osteoclasts increased five days after treatment. Hypofunctional findings, however, appeared seven and ten days after treatment. On the other hand, findings of distinguishable osteogenesis, e.g. well-developed golgi complex (G), endoplasmic reticulum (ER), mitochondria (M), were observed in the osteoblast and osteocyte, defining the strong influence of vitamine D in a large dose on the osteoblast-osteocyte system. Especially, the osteoblast seemed to be influenced earlier and to a greater degree. We concluded that 1 alpha-OH-D3 in doses of 0.02 and 0.08 microgram/kg/day hardly caused any morphological changes in the bone cell in our experiment.