RRR- and SRR-alpha-tocopherols are secreted without discrimination in human chylomicrons, but RRR-alpha-tocopherol is preferentially secreted in very low density lipoproteins

Journal Article · Sat Mar 31 23:00:00 EST 1990 · Journal of Lipid Research; (USA)

OSTI ID:6709146

Traber, M G; Burton, G W; Ingold, K U; Kayden, H J ^[1]

---

1. New York Univ. School of Medicine, NY (USA)

Five subjects ingested in a single oral dose containing 50 mg each of 2R,4'R,8'R-alpha-(5,7-(C2H3)2)tocopheryl acetate (d6-RRR-alpha-tocopheryl acetate) with natural stereochemistry, and of 2S,4'R,8'R-alpha-(5-C2H3)tocopheryl acetate (d3-SRR-alpha-tocopheryl acetate). These are two of eight stereoisomers in synthetic vitamin E. By day 1 the plasma and red blood cells were enriched fourfold with d6-RRR-alpha-tocopherol (P less than 0.004). The ratio of d6-RRR-/d2-SRR- further increased over the succeeding 4 days, because the d3-SRR- decreased at a faster rate than did the d6-RRR-stereoisomer. Plasma and lipoproteins were isolated at intervals during the first day, and daily for 3 days, from four additional subjects fed a mixture of equal amounts of the deuterated tocopherols. The plasma contained similar concentrations of the two forms until 11 h, when the d6-RRR-alpha-tocopherol concentration became significantly greater (P less than 0.05). The chylomicrons contained similar concentrations of the two deuterated tocopherols, but the VLDL (very low density lipoproteins) became preferentially enriched in d6-RRR-alpha-tocopherol by 11 h. The pattern of the deuterated tocopherols shows that during chylomicron catabolism all of the plasma lipoproteins were labeled equally with both tocopherols, but that during the subsequent VLDL catabolism the low and high density lipoproteins became enriched in d6-RRR-alpha-tocopherol. These results suggest the existence of a mechanism in the liver for assembling VLDL preferentially enriched in RRR- relative to SRR-alpha-tocopherol.

• OSTI ID: 6709146
• Journal Information: Journal of Lipid Research; (USA), Journal Name: Journal of Lipid Research; (USA) Vol. 31:4; ISSN JLPRA; ISSN 0022-2275
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CATABOLISM
CHYLOMICRONS
DEUTERIUM
ERYTHROCYTES
ESTERS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
LIPOPROTEINS
MAMMALS
MAN
MATERIALS
METABOLISM
NUCLEI
ODD-ODD NUCLEI
ORAL ADMINISTRATION
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
SECRETION
STABLE ISOTOPES
STEREOCHEMISTRY
TRACER TECHNIQUES
TRIGLYCERIDES
VERTEBRATES
VITAMIN E
VITAMINS