ULTIMOBRANCHIAL AND THYROIDIAN LOCALIZATION OF C-CELLS IN 2 COLUMBIDAE - PIGEON AND TURTLE-DOVE - AN ELECTRON MICROSCOPIC STUDY

In the two Columbidae we studied, C cells are present both in the ultimobranchial bodies and in the thyroid. Ultimobranchial bodies consist of cords which are made up of glandular cells and limiting cells. In certain peripheral regions of the thyroid, typical ultimobranchial cords are situated in the interiollicular and infracapsular spaces. Basal follicular C cells similar to those of the mammalian thyroid are rarely observed. The morphological characteristics of the C cells are identical whatever their situation may be: ultimobranchial or thyroidian, be it extrafollicular or basal follicular. The secretory granules differ slightly by their shape in the pigeon and the turtle-dove; their medium diameter varies more from one cell to another in the pigeon. Neuroglandular contacts exist at the level of the glandular cords situated in the ultimobranchial body and in the thyroid. Their signification is not clearly understood. © 1969 Springer-Verlag.