[Development and functional morphology of the Weibel-Palade-bodies in endothelial cells (author's transl)].

Our results presented indicate a transformation of multivesicular bodies from the Golgi-apparatus into Weibel-Palade-Bodies (WPB). A morphological series of different developmental phases of the WPB can be demonstrated by an increase of a certain intervesicular electron dense material. There is a striking coincidence with early developmental phases of myocardial Z-band material. The WPB are directly related to the microfilament system of the endothelial cells. The capillary endothelium of diseases and tumors of the human skin show a drastic reduction of the WPB-microfilament system towards the central parts of the tissue changes; this is accompanied with a simultaneous reduction of the pinocytotic activities. The endothelial cells are transformed into a conical shape with nearly an occlusion of the capillary lumen and an opening of the interendothelial junctions. This is interpreted as a loss of tone rather than a contraction of endothelial cells.