Any 3-oxo steroid that contains a double bond between positions 1 and 2.
| Member | Definition | Role |
|---|
| 1-testosterone | An anabolic steroid that differs from testosterone by having a 1,2-double bond instead of a 4,5-double bond in its A ring. A potent androgen with anabolic properties, it was legally sold as a prohormone in the U.S.A. until 2005, when it was reclassified as a Schedule III drug. | Delta(1)-dihydrotestosterone |
| 1,4-androstadiene-3,17-dione | A steroid that consists of androstane having double bonds at positions 1 and 4 and two keto groups at positions 3 and 17. | androsta-1,4-diene-3,17-dione |
| 1,5(10)-estradiene-3,4,17-trione | An o-quinone resulting from the formal oxidation of the dihydroxyphenyl moiety of 4-hydroxyestrone. | estra-1,5(10)-diene-3,4,17-trione |
| helvolic acid | A steroid C-21 acid having a 29-nordammarane skeleton substituted with an acetoxy group at C-16 and oxo groups at C-3 and -7, with double bonds at C-1, -17(20) and -24. | helvolic acid |