7648-2004 is specific for 17a-OH-Pregnenolone, but will also recognise 17a-OH-Progesterone. This antibody shows the following cross-reactivities with related molecules: Pregnenolone 0.25% Progesterone 1.1% 11-Deoxycortisol 0.7% Testosterone 0.5% 17a-OH-Pregnenolone is an intermediate in steroid biosynthesis and is produced through hydroxylation of pregnenolone by the enzyme 17-alpha-hydroxylase (CYP17A1).