Vitamin E deficiency in dogs does not alter preferential incorporation of RRR-alpha-tocopherol compared with all rac-alpha-tocopherol into plasma.
The plasma and lipoprotein transport of RRR and all rac-alpha-tocopherols, labeled with different amounts of deuterium [2R,4'R,8'R-alpha-[5-C2H3]tocopheryl acetate (d3RRR-alpha-tocopheryl acetate] and 2RS, 4'RS, 8'RS-alpha-[5,7-(C2H3)2]tocopheryl acetate (d6all rac-alpha-tocopheryl acetate), was studied in adult beagle dogs that had been fed a vitamin E-deficient (-E; two dogs) or supplemented (+E; two dogs) diet for two years. We set out to test the hypothesis that the activity of the hepatic tocopherol binding protein (which is thought to preferentially incorporate RRR-alpha-tocopherol into the plasma) is up-regulated by vitamin E deficiency. Labeled alpha-tocopherols increased and decreased similarly in plasma of both -E and +E dogs. Irrespective of diet, d3RRR-alpha-tocopherol was preferentially secreted in plasma. Thus, vitamin E deficiency in dogs does not markedly increase the apparent function of the hepatic tocopherol binding protein. We also studied vitamin E transport in a German Shepherd dog with degenerative myelopathy (DM). Based on the coincident appearance of d3RRR-alpha-tocopherol in plasma and chylomicrons, we suggest that the abnormality in DM may be associated with abnormal vitamin E transport resulting from an impaired function of the hepatic tocopherol binding protein.
Traber
M G
MG
Department of Medicine, New York University School of Medicine, New York 10016.
Pillai
S R
SR
Kayden
H J
HJ
Steiss
J E
JE
D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000097:blood; D004283:Dog Diseases / Q000097:blood; D004285:Dogs; D008074:Lipoproteins / Q000097:blood; D008297:Male; D013118:Spinal Cord Diseases / Q000097:blood / Q000662:veterinary; D013237:Stereoisomerism; D014810:Vitamin E / Q000097:blood*; D014811:Vitamin E Deficiency / Q000097:blood* / Q000662:veterinary
D002352:Carrier Proteins; D008074:Lipoproteins; C017763:alpha-tocopherol transfer protein; D014810:Vitamin E