<prompt> Rate limiting enzyme in testosterone synthesis17,20 lyase20,22-desmolase3-bHSD17-hydroxylase  <response>: Cholesterol is first acted upon by desmolase and a 6-carbon unit is cleaved off, forming 21 carbon steroid, pregnenolone It is the common precursor for all the steroid hormonesRef: DM Vasudevan, 7th edition, page no: 664 