Distribution of thyroid, parathyroid, and ultimobranchial hypocalcemic factors in birds. 1. Thyroid and ultimobranchial calcitonins in pigeons and pullets.

Abstract

Thyroid glands, parathyroid glands, and “ultimobranchial tissue samples” were dissected separately and identified histologically in pigeons. A rat biological assay for calcitonin was used to measure hypocalcemic activity in these pharyngeal glands of common pigeons, White Carneaux pigeons, and pullets. In the biological assay, log dose—response lines of avian tissue extracts were parallel to that of porcine calcitonin, and hypocalcemic responses of test animals to avian tissue extracts were not abolished by thyroparathyroidectomy. Porcine calcitonin was inactivated by incubation with pigeon and pullet serum; hypocalcemic activity of pullet ultimobranchial extract was reduced by incubation with calcitonininactivating material obtained from rat serum. Pigeon thyroid and ultimobranchial extracts produced hypophosphatemia as well as hypocalcemia in rats. In pullets, hypocalcemic activity was absent from thyroid glands but was present in parathyroid glands, ultimobranchial samples, and cervical nerves. In comm...