Plasma turnover of 3,4-didehydroretinol (vitamin A2) increases in vitamin A-deficient rats fed low versus high dietary fat.
Relationships between increased adiposity and fat-soluble vitamin storage and metabolism are poorly understood. To examine these associations, 6% or 21% dietary fat was fed to rats for 11 weeks and tissue vitamin A storage determined. Two levels of supplemental vitamin A were administered. At the end of the tenth week, 3,4-didehydroretinol (DR) was administered orally, and its kinetics were followed for 1 week in serum and tissues. Model-based compartmental analysis was applied to these data. Kidney total retinol (R) concentrations were elevated in rats fed 6% compared with 21% dietary fat (n = 24/group). The fractional transfer coefficient (FTC) describing the movement of tracer from plasma to extravascular stores was two times higher in the 6% compared with the 21% fat group. Consistent with the elevated renal R in 6% fat fed rats, there was a 2-fold increase in the FTC representing tracer distribution from plasma to kidney in the 6% compared with 21% fat group. Taken together with a fat main effect on renal vitamin A, our data support the evidence that faster turnover of kidney R may help set the mechanism governing vitamin A tissue distribution during deficiency. Rats fed 21% versus 6% dietary fat conserved hepatic R more efficiently.
Escaron
Anne L
AL
University of Wisconsin-Madison, Interdepartmental Graduate Program in Nutritional Sciences, Madison, WI, USA.
Green
Michael H
MH
Tanumihardjo
Sherry A
SA
D000273:Adipose Tissue / Q000378:metabolism; D050154:Adiposity / Q000502:physiology; D000818:Animals; D001835:Body Weight; D004041:Dietary Fats / Q000008:administration & dosage*; D004224:Diterpenes; D008099:Liver / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D009765:Obesity / Q000097:blood / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012176:Retinoids / Q000097:blood / Q000378:metabolism; D000084562:Retinyl Esters; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014802:Vitamin A Deficiency / Q000097:blood*
D004041:Dietary Fats; D004224:Diterpenes; D012176:Retinoids; D000084562:Retinyl Esters; C024366:vitamin A2; D014801:Vitamin A; C009166:retinol acetate