a 3-oxo-5alpha-steroid + A = a 3-oxo-Delta(4)-steroid + AH2
a 3-oxo-5alpha-steroid + a = a 3-oxo-delta(4)-steroid + ah2
a 3-oxo-5alpha-steroid + A = a 3-oxo-Delta(4)-steroid + AH2
a 3-oxo-5alpha-steroid + a = a 3-oxo-delta(4)-steroid + ah2