The Localization of the Vitamin A in the Mouse LIver as Revealed by Electron Microscope Radioautography

Abstract

Hypovitaminotic A mice were injected intravenously with tritiated vitamin A. They were killed at 10 min, 30 min, 1 hr and 5 hr after the injection. Livers were taken out and processed for electron microscope radioautography. Silver grains were found on fat droplets in the fat-storing cells as early as 10 min after the injection. Heavy labeling was not found in other hepatic structures than the fat-storing cell all through the time course. Constant labeling was not seen in the Kupffer cell. Labeling in the parenchymal cytoplasm was heavier at early time intervals than later. With the application of water mlsclble resin embedding, fat droplets appeared much electron denser and the number of silver grains increased. The results point out that vitamin A is not stored in the Kupffer cell but in the fat-storing cell.