Progesterone provides neuroprotection from Parkinson's progression

'Female' hormones helping yet again? PREMIUM CONTENT subscriber access

FIG. 1: Schematic representation of progesterone (P4) synthesis and metabolism in brain cells. In the mitochondria, the enzyme P450 side-change cleavage (P450scc) converts cholesterol into pregnenolone (PREG), which is further transformed into P4 in the endoplasmic reticulum in neurons and astrocytes. In neurons, as well as in astrocytes, P4 and testosterone may be metabolized by the enzymatic complex formed by (5ɑ-R) and 3ɑ-hydroxysteroid dehydrogenase (3ɑ-HSD) into dihydroprogesterone (DHP) and the tetrahydroprogesterone (THP), also known as allpregnanolone. P4 is converted into androstenedione by P450c17 in neurons and astrocytes which further metabolized into testosterone by 17ß-HSD. In neurons, androstenedione, as well as testosterone, may be converted by the enzyme P450 aromatase (ARO) to estrone and 17b-estradiol (17b-E2), respectively. -S S Andrabi, et al.

My past newsletter reported studies of estradiol healing neural injuries:

Now let us look at that luteal phase ovarian steroid, progesterone (P4). However, do note that P4 is also a steroid generated de novo in brain and retina. In both males and females, it can function as an anesthetic. The anxiolytic and anesthetic effects of progesterone result from its conversion to the metabolite, allopregnanolone.