Streptozotocin-induced diabetes in rats is associated with impaired metabolic availability of vitamin A (retinol).
Using streptozotocin-induced diabetic Wistar rats, studies were carried out to examine the metabolic availability of vitamin A in the plasma, liver and the retina of the eye. Control and diabetic rats were fed ad lib. on a semi-purified diet either with or without (basal) vitamin A supplementation, or pair-fed on the basal diet for 4 weeks. Despite the fact that diabetic rats consumed 48% more feed, they had lower plasma concentrations of retinol (P < 0.003). The decrease in plasma retinol concentration was a response to diabetes (or diabetes-induced trauma), since neither pair-feeding (P < 0.01) nor vitamin A supplementation altered this effect (P < 0.05). Furthermore, the hepatic concentrations of the vitamin in these animals remained elevated and this increase was greater in the supplemented diabetic group (P < 0.001). Decreases in 11-cis retinal (a component of rhodopsin) concentrations in the retina were also observed in diabetic animals. The increased hepatic and the decreased plasma and retina vitamin A levels suggest a defect in the transport of the vitamin from the liver.
Tuitoek
P J
PJ
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
Ziari
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S
Tsin
A T
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Rajotte
R V
RV
Suh
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Basu
T K
TK
D000818:Animals; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism; D014801:Vitamin A / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics
D014801:Vitamin A