3α,21-Dihydroxy-5α-pregnan-20-one (THDOC) is a positive allosteric modulator of the γ-aminobutyric acid A receptor (GABAA). By modulating GABAA receptor, THDOC allows sustained hyperpolarization and an increase in chloride influx and membrane conductance in neurons. THDOC, thus modulates neuronal excitability. It possesses anxiolytic, anticonvulsant and sedative properties. The levels of THDOC show variation in different physiological states. A low THDOC level in the mensural phase is speculated to play a role in the pathogenesis of catamenial epilepsy (CE) in women. However, elevated levels are reported in depression. THDOC may have an indirect role in the hypothalamic-pituitary–adrenal (HPA) axis activation during acute stress.
