Exchange of sterols between myelin and other membranes of developing rat brain.
1. The effect of inhibition of cholesterol synthesis by a hypocholesterolaemic drug (AY-9944) was studied in rat brain during development. 2. At 2 weeks after administration of AY-9944 to young rats 7-dehydrocholesterol accounted for half the total sterol of myelin and other subcellular components. 3. At 4 weeks after injection of the drug 7-dehydrocholesterol had disappeared whereas the cholesterol content of myelin had increased by an equivalent amount. Our studies show that purified myelin has low 7-dehydrocholesterol reductase activity and suggest that 7-dehydrocholesterol is largely converted into cholesterol outside the myelin sheath. 4. Resultant cholesterol may be re-incorporated into myelin by an exchange process. 5. The metabolism of sterols in developing brain is discussed.
D000085:Acetates / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002247:Carbon Isotopes; D002784:Cholesterol / Q000032:analysis / Q000096:biosynthesis; D002849:Chromatography, Gas; D003510:Cyclohexanes; D005260:Female; D008297:Male; D008861:Microsomes / Q000032:analysis; D008928:Mitochondria / Q000032:analysis; D009186:Myelin Sheath / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D013261:Sterols / Q000032:analysis / Q000378:metabolism*
D000085:Acetates; D002247:Carbon Isotopes; D003510:Cyclohexanes; D013261:Sterols; D002784:Cholesterol