pregnadiene pregnadiene a pregnadiene is a diene derivative of a pregnane. dienes have two double bonds. the first is usually between carbon 4 and carbon 5 on ring a. 6-ene the second can be between carbons 6 and 7 on ring b: chlormadinone acetate (progestin) cyproterone acetate (antiandrogen) dydrogesterone (progestin) megestrol acetate (progestin, antineoplastic, appetite stimulant) canrenone (aldosterone antagonist) medrogestone (progestin) 1-ene the second can also be between carbons 1 and 2 on ring a: fluocinolone acetonide (glucocorticoid) triamcinolone (glucocorticoid)