| abstract |
1α-hydroxy-vitamin D derivatives represented by formula ##STR1## wherein R 1 represents a hydrogen atom or a hydroxyl group; and R 2 represents a straight-chain or branched C 2 -C 7 alkyl, C 2 -C 7 alkenyl, or C 2 -C 7 alkynyl group. The compounds exhibit calcium metabolism regulating activity and differentiation stimulating activity on tumor cells, and are useful as treating agents for diseases caused by abnormal calcium metabolism, such as osteoporosis and osteomalacia, or as antitumor agents. |