| Abstract: | The effect of chloroquine on the intralysosomal degradation of cell-coat glycoproteins in cultured intestinal absorptive cell was investigated by silver proteinate staining. The results of this staining method, which is specific for carbohydrate containing macromolecules such as glycoproteins and mucopolysaccharides, showed that in the presence of the drug considerable amounts of silver proteinate-positive material accumulated in one type of lysosome-like body: the dense bodies. The staining pattern of other cell organelles was not affected by chloroquine. The presence of the drug in the culture medium also resulted in the occurrence of numerous small vesicular structures in the matrix of the dense bodies. These showed a similar size and structure to those present in the other type of lysosome-like body: the multivesicular bodies. This observation, together with earlier autoradiographical data, suggests that cell-coat material is transferred from multivesicular to dense bodies by fusion between these organelles. This study thus provides further evidence for a regulatory mechanism of cell-coat glycoprotein transport by the lysosome-like bodies in human intestinal absorptive cells. |
