Figure 4.

Neurosteroid biosynthetic machinery and neurosteroid levels are dysregulated in multiple sclerosis. Schematic representation of the enzymatic reactions involved in allopregnanolone biosynthesis (A). Analysed by real-time reverse transcription–PCR, transcript levels of different isoforms of 3β-hydroxysteroid dehydrogenase (HSD) were not changed in the brains of patients with multiple sclerosis (B). However, transcript levels of 5α-reductase 1 (C), as well as AKR1C2 (D) were significantly lower in patients with multiple sclerosis compared with control subjects. Western blot analysis also showed reduced protein levels of 3α-HSD in multiple sclerosis (E and F). Gas chromatography–mass spectrometry analysis disclosed unaltered levels of pregnenolone in the brains of patients with multiple sclerosis (G), whereas the levels of dehydroepiandrosterone (H) and allopregnanolone (I) were significantly reduced in these subjects compared with controls. The levels of the minor 3α5β-tetrahydroprogesterone isoform were not changed in brain (J). Transcript levels are represented as relative fold change ± SEM. Neurosteroid levels are shown as mean ± SEM. Non-multiple sclerosis control subjects included 10 individuals (five males; mean age: 59 ± 6.1 years) and the multiple sclerosis group included 16 patients (seven males, mean age 55 ± 7.8 years; Student's t-test; *P < 0.05; mRNA = messenger RNA; MS = multiple sclerosis; nMS = non-multiple sclerosis controls; RFC = reduced folate carrier).