The fine structure of dense lysosomes isolated from rat spleen

A dense fraction from rat spleen was shown to consist of membrane bound organelles of varying shape and size which were packed with electron dense particles with the appearance of ferritin. Electron microscope microanalysis confirmed that iron was present in the organelles and the amount correlated with the density as noted in transmission electron microscopy. The organelles also stained, positively for acid phosphatase and, therefore, confirmed the biochemical findings that dense lysosomes (L30) had been isolated. The role lysosomes play in the degradation of red blood cells, and as possible sites of iron storage, are briefly discussed.