#$%^&*AU2013201280A120130321.pdf#####ABSTRACT A main object of the invention is to provide a novel useful vitamin D3 derivative, which has an excellent vitamin D3 activity and, as compared with conventional vitamin D3 derivatives, has a relatively small amount of influence on the systemic calcium metabolism. The invention includes a 9,10-secopregnane derivative of the following general formula [1] and a pharmaceutical composition containing it as active ingredient. [Formula 1] R 3 200 CH3 Y R1 16 0 R 2 Z a Rb HO _ OH Rc Rd In the general formula [1], the following partial structure between the 16-position and the 17-position means a single bond or a double bond: [Formula 2] 117Y is a single bond, an alkylene, an alkenylene or phenylene R and R2 are the same or different, each represents hydrogen, an alkyl or a cycloalkyl or R1 and R2 taken together with the adjacent carbon atom, form a cycloalkyl R3 is hydrogen or methyl Z is hydrogen, 1112 hydroxy or -NR R 118
