[Uptake of horseradish peroxidase (HRP) in omental milk spot cells of the mouse: an electron microscope study (author's transl)].

In adult dd-mice horseradish peroxidase (HRP) was injected intraperitoneally, and the response of omental milk spot cells was systematically observed by electron microscopy. In the omental milk spots, macrophages were very active in uptake of HRP. However, the activity was different between macrophages which existed in the superficial zone of milk spots and those which were seen in the deeper zone and the fatty tissue deep to the milk spots. Thus the two types of macrophages could be distinguished not only by structural details but also by uptake response to HRP. Lymphoid cells in the spots could take up very small amounts of HRP just after HRP injection, whereas lymphocytes showed no HRP uptake. Mesothelial cells and fibrocytes could take up small amounts of HRP.