11alpha hydroxyprogesterone article 6 unclassified drug 6 11beta hydroxysteroid dehydrogenase 4 3alpha hydroxy 5alpha pregnan 20 one derivative 4 Chinese hamster 4 animal cell 4 competitive inhibition 4 conference paper 4 cyclopropylketone derivative 4 dehydropregnenolone acetate 4 drug structure 4 drug synthesis 4 enzyme activity 4 enzyme inhibition 4 enzyme kinetics 4 genetic complementation 4 genetic transfection 4 glycosylation 4 ketone derivative 4 mercury derivative 4 neurosteroid derivative 4 nonhuman 4 potassium excretion 4 pregnenolone derivative 4 priority journal 4 reaction analysis 4 sodium retention 4 steroid 4 1,11-Epoxypregnane 2