Names of fundamental structures most often used in steroid nomenclature

carbon atoms present (as numbered in structure 6) naturally occurring

general

classes examples shown in text

gonane 1–17 none gonane* (1)

estrane 1–18 estrogens estradiol (17f)

androstane 1–19 androgens androstane* (2–5); testosterone (17e); androstanedione (17c)

pregnane 1–21 gestogens and adrenal steroids progesterone (17a); cortisol (17b); aldosterone (17d); batrachotoxin (14)

cholane 1–24 bile acids cholic acid (10a); sodium sodium glycocholate (10b)

cholestane 1–27 sterols cholesterol (16d); scymnol (11a)

ergostane 1–28 sterols ergosterol (8); cyasterone (22)

stigmastane 1–29 sterols stigmasterol (7); antheridiol (12)

lanostane 1–27; 30–32 trimethyl sterols lanosterol (16c);

22,25-oxidoholothurinogenin (13)

cardanolide 1–23 cardiac glycosides digitoxigenin (23)

bufanolide 1–24 toad poisons bufotoxin (24)

spirostan 1–27 sapogenins dioscin (25)

*Gonane and androstane themselves do not occur in nature.