Utilization of carbon from dietary polyunsaturates for brain cholesterol synthesis during early postnatal development in the rat: a 13C NMR study.
Incorporation of 13C from a dietary precursor into cholesterol was studied in neonatal rats. Rats were given uniformly 13C-enriched polyunsaturated fatty acids intragastrically and total lipid extracts of liver and brain were analyzed by 13C-NMR 1, 4, 8, and 15 days later. 13C-enrichment was detected in brain but not in liver cholesterol. Maximal 13C-labeling was observed 4 days after injection of the label. Spectra revealed that 70% of newly incorporated 13C had 13C as an adjacent neighbor, the other 30% had 12C as the neighbor. Double quantum NMR revealed the arrangement in the cholesterol skeleton of the 13C-13C pairs transferred from precursors to cholesterol. Desmosterol, an intermediate of cholesterol synthesis, was identified in the spectra of brain lipids. Comparison of 13C-13C unit arrangements in both cholesterol and desmosterol allowed carbons 26 and 27 of desmosterol to be unambiguously assigned.
Likhodii
S S
SS
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Canada.
Cunnane
S C
SC
D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D002244:Carbon / Q000378:metabolism*; D002247:Carbon Isotopes; D002784:Cholesterol / Q000096:biosynthesis* / Q000737:chemistry; D003897:Desmosterol / Q000737:chemistry; D004042:Dietary Fats, Unsaturated / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D051381:Rats; D013997:Time Factors; D014020:Tissue Extracts / Q000737:chemistry
D002247:Carbon Isotopes; D004042:Dietary Fats, Unsaturated; D005231:Fatty Acids, Unsaturated; D014020:Tissue Extracts; D003897:Desmosterol; D002244:Carbon; D002784:Cholesterol