Akwa Y, Schumacher M, Jung-Testas I, Baulieu E E
Laboratoire des Hormones, INSERM U33, Bicêtre, France.
C R Acad Sci III. 1993;316(4):410-4.
Pregnenolone (PREG) and corticosterone were measured in sciatic nerves and plasma of adult male rats by radioimmunoassays. Concentrations of PREG were higher in nerves than in plasma, whereas those of corticosterone were lower. In contrast to corticosterone, PREG was not reduced by castration and adrenalectomy, strongly suggesting a local synthesis of this steroid independent of glandular sources. In fact, Schwann cells in culture produced PREG from 25-hydroxy-cholesterol. They also converted PREG and dehydroepiandrosterone to the respective 7 alpha-hydroxylated metabolites and to 5-androstene-3 beta,17 beta-diol. The metabolism of steroids was increased when Schwann cells were grown in the presence of insulin and forskolin. These findings may have important implications for understanding the regeneration of peripheral nerves.
采用放射免疫分析法测定成年雄性大鼠坐骨神经和血浆中的孕烯醇酮（PREG）和皮质酮。坐骨神经中PREG的浓度高于血浆，而皮质酮的浓度则较低。与皮质酮不同，去势和肾上腺切除不会降低PREG，这强烈表明这种类固醇是独立于腺体来源进行局部合成的。事实上，培养的雪旺细胞可由25-羟基胆固醇生成PREG。它们还将PREG和脱氢表雄酮转化为各自的7α-羟基化代谢产物以及5-雄烯-3β,17β-二醇。当雪旺细胞在胰岛素和福斯高林存在的情况下生长时，类固醇的代谢会增强。这些发现可能对理解周围神经的再生具有重要意义。
