title: Ultimobranchial gland of the domestic fowl. Two types of secretory cells involved in calcitonin metabolism.
abstract: The ultimobranchial gland (UBG) of birds is particularly rich in calcitonin, the hypocalcaemic hypophosphataemic hormone, that is secreted by the C-cells of the mammalian thyroid. The principal cells of the UBG have a striking resemblance with the mammalian C-cells, i.e., they possess small intracytoplasmic dense-core secretory granules, 150-300 nm in diameter. The gland also contains a second, morphologically distinct, endocrine cell type with larger granules, 500-800 nm in diameter. A sensitive immunocytochemical reaction was developed with the use of antibodies against salmon calcitonin. By means of this technique the presence of calcitonin-immunoreactive molecules was demonstrated in both secretory cell types of the UB gland of the chicken. This gland can thus be considered as a homogeneous calcitonin-producing tissue. Whether the secretory products are identical is discussed and differences in the secretory pathways are suggested.
mesh_terms: D000818:Animals; D002116:Calcitonin / Q000378:metabolism*; D002645:Chickens; D005455:Fluorescent Antibody Technique; D008854:Microscopy, Electron; D011863:Radioimmunoassay; D014460:Ultimobranchial Body / Q000166:cytology* / Q000378:metabolism
chemical_list: D002116:Calcitonin