The object of the present invention is to provide anovel and useful vitamin D3 derivative which does not havemuch effect on the systemic calcium metabolism whileretaining an excellent vitamin D3 activity.The present invention may include a9,10--secopregnane derivative represented by the followinggeneral formula [1] and a pharmaceutical compositioncontaining the same as an active ingredient.(see formula 1)In the general formula [1], Y represents (1) asingle bond, (2) alkylene, (3) alkenylene or (4)phenylene； R1 and R2 are same or different and eachrepresents (1) hydrogen, (2) alkyl or (3) cycloalkyl, R1and R2 taken together with the carbon atom adjacentthereto may form a cycloalkyl； R3 represents hydrogen ormethyl； and Z represents (1) hydrogen, (2) hydroxy or (3)-NR11R12.
