[Reorganisation of thyroid follicular cells in culture. Effect of collagen on the orientation of cell polarity].

In contact with a collagen gel, thyroid follicular cells form a basal pole. A monolayer, with the apical side facing the culture medium is formed when cells are seeded on a collagen layer. In contrast cells reorganize into follicle-like structures when they are embedded in the collagen gel. If vesicles which have their apical pole in contact with the culture medium are embedded in the gel, collagen-cell interaction induced the inversion of cell polarity giving follicular structures. In addition after being overlaid with a collagen layer, cells forming a monolayer reorgnaize into follicles. The apical pole is formed on the free surface of the monolayer or on the internal side of structures embedded in collagen which differentiate into follicles.