Expression of cytochrome P450scc mRNA in the hippocampus of patients with temporal lobe epilepsy

THE hippocampus is one of the target areas of neurosteroidal action. Expres sion of cytochrome P450scc (P450scc, CYP11A1), one of the key enzymes in st eroid metabolism, results in de novo synthesis of the neurosteroid pregneno lone. We used a competitive RT-PCR assay to quantify the amount of P450scc mRNA in hippocampal tissue specimens obtained at neurosurgery from patients with temporal lobe epilepsy (TLE). P450scc mRNA is expressed similar to 20 0 times lower in the hippocampus than in adrenal tissue known for high P450 scc expression. P450scc mRNA concentrations were significantly higher in th e hippocampus of women (1.72 +/- 0.36 aU, arbitrary units; mean +/- s.e.m.) than of men (0.92 +/- 0.15 aU, p < 0.004). Our data show for the first:tim e the sex-dependent expression of P450scc mRNA in the hippocampus of patien ts with TLE. (C) 1999 Lippincott Williams & Wilkins.