<prompt> Progesterone is synthesized fromPregnenolone17-HydroxypregnenolonePregnanediolPregnanetriol  <response>: Pregnenolone is conveed to progesterone by the action of two smooth endoplasmic reticulum enzymes, 3a-hydroxysteroid dehydrogenase 3a-OHSD and D5,4-isomerase.Ref: Harper;s Biochemistry; 30th edition; Page no: 503 