Pregnanes

Pregnanes are steroid derivatives with carbons present at positions 1 through 21.

Most biologically significant pregnane derivatives fall into one of two groups: Pregnenes and Pregnadienes.

Pregnenes
Pregnenes have a double bond. Examples include:
 * cortisone
 * hydrocortisone
 * progesterone

Pregnadienes
Pregnadienes have two double bonds. Examples include:
 * cyproterone
 * danazol
 * fluocinonide