The role of intracellular lumina in the repolarization process of a colonic adenocarcinoma cell line.

When glucose is added to the culture medium, some cells of the undifferentiated HT-29 line derived from a human colonic adenocarcinoma develop spherical structures, demonstrated to be intracellular by the ruthenium red staining method, which are bordered with microvilli, contain osmiophilic substances and resemble intracellular lumina. When glucose is replaced by galactose in the culture medium, the cells differentiate apical membranes bordered with microvilli. Our observations suggest that these new apical membranes correspond to the membranes of intracellular lumina which have opened outside the cells. We suggest that intracellular lumina may represent "compensation" for loss of polarity of epithelial cells and may be an important step in the repolarizing process of the cells.