Steroid hormone signaling between Schwann cells and neurons regulates the rate of myelin synthesis.
Fluorescence digital imaging microscopy was used to develop a method that allows the continuous monitoring and quantitative measurement of a single myelin internode throughout its development. Using this technique, steroid hormones such as progesterone and dexamethasone were shown to reduce the time required for the initiation and to regulate the rate of myelin synthesis. Progesterone was capable of increasing the rate of myelin synthesis in Schwann cell/neuronal co-cultures in a dose-dependent manner. RT-PCR and in situ hydridization studies revealed that the mRNAs for P450scc and 3beta-hydroxysteroid dehydrogenase, the enzymes involved in progesterone biosynthesis, were induced at the onset of myelin synthesis. The progesterone receptor protein translocated into the nucleus of the neurons during myelin synthesis, suggesting that progesterone could also be affecting neuronal gene expression. Changes in gene expression caused by progesterone are being examined to identify additional factors that may control myelin formation.
Department of Biochemistry and Neuroscience Program, University of Illinois, Urbana, Illinois 61801, USA.
Paul M
PM
Rodriguez-Waitkus
Andrew J
AJ
Lafollette
Benjamin K
BK
Ng
Thant S
TS
Zhu
H Edward
HE
Conrad
Michael
M
Glaser
D000818:Animals; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D012739:Gonadal Steroid Hormones / Q000494:pharmacology* / Q000502:physiology; D009186:Myelin Sheath / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D012583:Schwann Cells / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology
D012739:Gonadal Steroid Hormones