IMPAIRMENT OF VITAMIN-A UPTAKE BY RAT HEPATOCYTES AND FAT-STORING CELLS DETERMINED BY MONENSIN - MORPHOLOGICAL OBSERVATIONS

The action of the Na+/H+ antiport monensin on vitamin A uptake by rat liver has been studied in vivo. The quick-fading autofluorescence of v itamin A has been used for the determination of vitamin A uptake by th e liver. Pretreatment of rats intraperitoneally with monensin decrease s the uptake of vitamin A by hepatocytes and its transfer for storage to fat storing cells. Pretreatment of rats intraperitoneally with vita min A for a short time, then with monensin, shows that the hepatocytes no longer transfer vitamin A to fat storing cells for storage. These results might indicate that monensin impairs the uptake of vitamin A b y the hepatocytes and might also impair the transport of vitamin A fro m parenchymal to perisinusoidal cells.