Lymphatic absorptive process of vitamin E and phagocytosis by alveolar macrophages in rats

The relationship between the absorption of vitamin E (VE) after intragastric administration and phagocytic activity of alveolar macrophages (AM) was examined using thoracic duct-cannulated rats. VE concentration in thoracic duct lymph fluid increased significantly in comparison to the control rats, and peaked 3 hr after administration of VE. The level of VE in the lung peaked 9 hr after administration, and was about two times higher than that of the control rats. After administration of VE, lipid droplets accumulated within the alveolar septa of the lungs. The levels of VE also peaked in bronchoalveolar lavage fluid (BALF) and in AM 9 hr after administration. Phagocytosis activity of IgG-opsonized-sheep red blood cells by AM gradually increased as the duration after administration increased. The activity of macrophage-activating factor (MAF) in BALF from rats administered VE also increased phagocytosis by AM from untreated rats. These results indicate that VE may directly affect the function of AM through activating MAF in the BALF of lungs after absorption from the thoracic duct without being metabolized in the liver.