[Neurosteroids: trophic effects in the nervous system].
Some steroids, named "neurosteroïds", can be synthesized from cholesterol within both the central and peripheral nervous systems. Thus, pregnenolone and progesterone persist in the brain and in peripheral nerves long after removal of the steroidogenic endocrine glands by castration and adrenalectomy. The role of neurosteroids during the development of the nervous system is not well known, although they are synthesized by glial cells and some populations of neurons already during embryonic life. Cell culture experiments suggest that neurosteroids may influence the survival and differentiation of neurons and glial cells. In the adult nervous system, neurosteroids play an important role during regeneration. Progesterone is indeed synthesized by Schwann cells in peripheral nerves, where it plays an important role in the formation of new myelin sheaths after lesion. This is the first demonstration of a vital role for a neurosteroid in the nervous system.
Schumacher
M
M
U488 INSERM, Le Kremlin-Bicêtre, France. schuma@kb.inserm.fr
Robert
F
F
Baulieu
E E
EE
D000315:Adrenalectomy; D000818:Animals; D001921:Brain / Q000502:physiology*; D002369:Castration; D006801:Humans; D009424:Nervous System Physiological Phenomena; D011284:Pregnenolone / Q000502:physiology*; D011374:Progesterone / Q000502:physiology*; D013256:Steroids / Q000494:pharmacology*
D013256:Steroids; D011374:Progesterone; D011284:Pregnenolone