of the 18 steroids tested , progesterone , 17 alpha-hydroxyprogesterone , and 11 beta,17 alpha-dihydroxyprogesterone were found to be the only steroids to serve as substrates for this adrenal enzyme , a much higher degree of substrate specificity than has been reported for a hepatic 21-hydroxylase .
C0033308
progesterone
C0002328
dihydroxyprogesterone