Steroid metabolism

Please note; This chart is not close to complete. It describes the process of steroidogenesis, by which many of the hormones which may later act as pheromones are produced by the body. Here's a more updated, complex and detailed chart.

Steroidogenesis

Other Pathways

Pregnenolone related

(some info may be redundant with th above chart but the 16-ene synthetase seems a new addition)

• Pregnenolone can be converted to progesterone. The critical enzyme step is two-fold using a 3-beta-hydroxysteroid dehydrogenase and a delta 4-5 isomerase. The latter transfers the double bond from C5 to C4 on the A ring. Progesterone is the entry into the delta-4-pathway, resulting in production of 17-hydroxy progesterone and androstenedione (aka androstadienone), precursor to testosterone and estrone. Aldosterone and corticosteroids are also derived from progesterone or its derivatives.
• Pregnenolone can be converted to 17-hydroxy-pregnenolone by the enzyme 17α-hydroxylase (CYP17A1). Using this pathway, termed delta-5 pathway, the next step is conversion to dehydroepiandrosterone (DHEA) using a desmolase. DHEA is the precursor of androstenedione.
• Pregnenolone can be converted to androsta-5,16-dien-3 beta-ol by 16-ene synthetase.

source

In the body, most pregnenolone is rapidly converted to pregnenolone sulfate.