R2 R 母核名称 R R1 R2 甾烷 H H H 雌甾烷 H CH3 H 雄甾烷 CH3 CH3 H 孕甾烷 CH3 CH3 CH3CH2 胆烷 CH3 CH3 CH3 CH2 CH2(CH3)CH 胆甾烷 CH3 CH3 (CH3)2CH CH2 CH2 CH2(CH3)CH R R1 R2 H 母核名称 R R1 R2 甾烷 H H H 雌甾烷 H CH3 H 雄甾烷 CH3 CH3 H 孕甾烷 CH3 CH3 CH3CH2 胆烷 CH3 CH3 CH3 CH2 CH2 (CH3) CH 胆甾烷 CH3 CH3 (CH3)2CH CH2 CH2 CH2 (CH3) CH