3d image of gonane skeletal formula

gonane cyclohexane cyclopentanperhydrophenanthrene cyclopentane perhydrocyclopentaphenanthrene tetracyclic hydrocarbon steroids skeleton steroid nucleus hormones steroid steroidal stereoisomer tautomer isomer estrane androstane pregnane stubs hormone hormonal function endocrine endocrinology prohormone analogue biosynthesis biosynthetic intermediate biogenesis substrate precursor synthesis derivative bioprecursor metabolic endogenous molecule molecular formula skeletal structural structure biochemistry biomolecule bioactive biochemical 3d