3Beta Hydroxysteroid dehydrogenase

3 β-Hydroxysteroid dehydrogenase, or 3 β-HSD is a group of steroidogenic enzymes.

The main steroidogenic isoform, 3 β-HSD I, catalyzes the conversion of pregnenolone to progesterone, the conversion of 17-Hydroxypregnenolone to 17-Hydroxyprogesterone, and the conversion of DHEA to Androstenedione.

It is mainly expressed in the gonads and the adrenal cortex.