Effects of an Avian Ultimobranchial Extract in the Domestic Fowl

Abstract

THE existence of a hypocalcemic principle which is involved in calcium homeostasis in mammals is now well established (Hirsch and Munson, 1969). This hormone, termed calcitonin, is produced by cells derived from the last branchial pouch (Bussolati and Pearse, 1967). In mammals these cells become intimately and extensively associated with thyroid parenchyma and are termed “C” cells (Pearse and Carvalheira, 1967). In birds, reptiles, amphibians, and fishes, however, they are retained in separate entities, the paired ultimobranchial glands (Dudley, 1942).Ultimobranchial (UB) preparations from the chicken produced hypocalcemia when injected into the rat (Copp et al., 1967; Tauber, 1967); however, they had little or no activity when administered to the newly-hatched chick (Urist, 1967). In order to shed light on this apparent discrepancy, it was the objective of this study to investigate the effects of chicken ultimobranchial preparations on plasma levels of calcium in birds of different ages. Plasma magnesium…