FLASK CELLS AND FLASK-SHAPED GLANDULAR CELLS OF AMPHIBIAN SKIN SPECIFICALLY PRODUCE FUCOSE-RICH GLYCOPROTEINS

A battery of horseradish peroxidase-conjugated lectins has been employ ed as a cytochemical tool for the labelling of specific cell types in amphibian epidermis. Among the lectins used, only Ulex europaeus I (UE A I) showed specific reaction with the cytoplasm of flask cells. In ad dition, UEA I stained flask-shaped secretory cells in dermal glands an d a reaction on glandular ductal cells was also observed. At the elect ron microscopic level, lectin binding was found in granules distribute d among mitochondria in the cytoplasm of flask cells and in larger muc ous granules of flask-shaped glandular cells, which were released into the lumen. UEA I also stained the extracellular space above flask cel ls. The labelling was due mainlty to a glycoprotein of mol. wt. approx . 27 kDa. Structural and cytochemical similarities between flask cells and flask-shaped cells of dermal glands could be a consequence of a c ommon secretory role of both cell types.