[Ultrastructural study of the follicular cells of the adenohypophysis of the chicken].

As in other species, a network of follicular cells linked together by functional complexes can be observed by electron microscopy in the adenohypophysis of the chick. No secretory granules are seen in the follicular cells. They are connected with each other by thin and long processes inserted between the glandular cells and the perivascular spaces. They limit, by their follicular pole, submicroscopic cavities of irregular size and shape. They are empty or occupied by a material of variable density. These cells exist very precociously in the embryo but their characteristic organisation to form a network is observed only on the 16th day of incubation. Our experimental study made it possible to evoke, as a number of other authors, that they play a role in the functions of support, exchange, transport of secretory material or phagocytosis.