Precursors for cholesterol synthesis (7-dehydrocholesterol, 7-dehydrodesmosterol, and desmosterol): cholesterol/7-dehydrocholesterol ratio as an index of development and aging in PNS but not in CNS.
In rat sciatic nerve, the 7-dehydrocholesterol content decreased dramatically during the postnatal period and slowly during adulthood and aging. In contrast, the 7-dehydrodesmosterol content peaked at 14 days and was nearly undetectable after 60 days. The desmosterol content peaked at 21 days and was nearly undetectable after 1 year. The cholesterol content increased up to 21 days and remained nearly constant thereafter. In brain (in contrast to sciatic nerve), 7-dehydrodesmosterol and desmosterol contents decreased dramatically during development and slightly during adulthood and aging; the 7-dehydrocholesterol content peaked at 21 days and remained constant during aging. Only 7-dehydrocholesterol was dramatically more concentrated in PNS than in CNS. In brain, the cholesterol/7-dehydrocholesterol ratio increased during development and remained stable after 6 months. In contrast, in sciatic nerve, this ratio continuously increased during development and aging (950-fold between 5 days and 18 months). Thus, the cholesterol/7-dehydrocholesterol ratio is a useful biochemical index of development and aging in the PNS.
Bourre
J M
JM
INSERM U.26, Hôpital Fernand Widal, Paris, France.
Clément
M
M
Gérard
D
D
Legrand
R
R
Chaudière
J
J
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002762:Cholecalciferol / Q000378:metabolism* / Q000031:analogs & derivatives; D002775:Cholestadienols / Q000378:metabolism*; D002784:Cholesterol / Q000096:biosynthesis / Q000378:metabolism*; D003684:Dehydrocholesterols / Q000378:metabolism*; D003897:Desmosterol / Q000378:metabolism*; D010525:Peripheral Nerves / Q000254:growth & development / Q000378:metabolism*; D011355:Prodrugs / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000378:metabolism
D002775:Cholestadienols; D003684:Dehydrocholesterols; D011355:Prodrugs; C007041:cholesta-5,7,24-trien-3 beta-ol; D002762:Cholecalciferol; D003897:Desmosterol; D002784:Cholesterol; C016705:7-dehydrocholesterol