Precursor to metabolite: Pregnenolone to Allopregnanolone

Pregnenolone is converted to Allopregnanolone by 3-beta-HSD → 5-alpha-reductase → 3-alpha-HSOR.

The pair

Pregnenolone — The steroid every other steroid hormone is built from; a sigma-1 agonist, sold over the counter.
Allopregnanolone — Progesterone-derived neurosteroid and a potent positive modulator of GABA-A — the model for brexanolone.