[In the dying cell secretory protein diffuses through the membranes into the cytosol]

Anti-horseradish peroxidase IgG (a-HRP) secreting hybridoma lymphoblasts grown subcutaneously in recipient mice have been studied light and electron microscopically 30-120 min following capitation of the animals. Conventional HRP-DAB immunocytochemical staining was performed for demonstration of a-HRP which in the living cells was restricted to the rough endoplasmic reticulum, the perinuclear cisterns, the Golgi apparatus and some microvesicles. 30 min after death in a number of the cells a-HRP began to invade the cytosol leaving, however, the nucleus and mitochondrial matrix free of the secretory marker. 30 to 90 min later staining intensity became similar in all cellular structures thereby making an impression of overall a-HRP spreading throughout the cell. In the light of these findings and the data obtained by other investigators a conclusion is made on the diffusion of macromolecules across intracellular membranes as a result of considerable post-mortem disturbances in membrane permeability.