Cellular localization of liver vitamin A in rats given total parenteral nutrition (TPN) solutions intravenously or orally
McKenna, M.C.; Robison, W.G.; Bieri, J.G.
Journal of Nutrition 113(6): 1176-1186
1983
ISSN/ISBN: 0022-3166 PMID: 6406651 Document Number: 204098
The cellular localization of liver vitamin A was estimated in rats, depleted of retinol, with vitamin A stores repleted orally or by total parenteral nutrition (TPN), to detrmine if the route of vitamin administration affected storage location. Solutions containing dispersions of retinyl palmitate were infused into the TPN group and given by mouth to controls for 5 days. The site of liver vitamin A storage was estimated by correlating vitamin A-specific autofluorescence in frozen sections with the presence of lipid droplets in oil red O preparations, in 1- mu m Epon sections and in sections prepared for electron microscopy. Both the vitamin A autofluorescence and oil red O staining were concentrated along the sinusoids in rats both infused with TPN solution and orally fed. Examination of thin sections at higher magnification showed that most of the lipid droplets containing vitamin A were localized near the sinusoidal side of the parenchymal cell cytoplasm, corresponding to the vitamin A autofluorescence and red O distribution. There were very few lipid droplets in the stellate cells and none in the Kupffer cells. The results indicate that vitamin A infused in TPN solutions is stored in the same cellular location as vitamin A taken by mouth.