Ontogeny of chicken ultimobranchial glands studied by an immunoperoxidase method using calcitonin, somatostatin and 19S-thyroglobulin antisera.

The ontogeny of the ultimobranchial glands in chickens from 9-day-old embryos to adults was investigated by the immunoperoxidase method using anti-calcitonin, anti-somatostatin and anti-19S-thyroglobulin antisera. During embryonic development, the chick ultimobranchial glands consisted of solid cell clusters. Calcitonin immunoreactivity began to appear at 16 days of incubation and rapidly increased at late periods of incubation. At the time of hatching, almost all of the epithelial cells in the ultimobranchial glands exhibited the immunoreaction for calcitonin. Cyst structures showing various sizes, shapes and luminal contents were consistent features of the ultimobranchial glands after hatching. As age proceeded, the cysts and loose connective tissues gradually increased in the glands. In adult chickens, the calcitonin cells came to be interspersed among them and the number of the cells per unit area was very small, compared with that in young animals. No immunoreaction for somatostatin was found in the ultimobranchial glands of chickens of all ages examined. In the glands there were no cells immunoreactive to the 19S-thyroglobulin antiserum. Further, neither cyst epithelium nor luminal contents were stained with the antiserum.