Histological and immunohistochemical study on ontogeny of the endocrine cells in the quail gizzard

The pre- and post-hatching development and differentiation of the endocrine cells in quail gizzard were examined histologically and immunohistochemically. A total of 158 heads (from 5th d of incubation to adult) were used in this study. The formation of gizzard tubular glands began from 11th d of incubation. 8 kinds of endocrine cells, argyrophil cells, and gastrin releasing polypeptide (GRP)-, 5-hydroxytryptamine (5-HT)-, somatostatin-, glucagon-, avian pancreatic polypeptide (APP)-, neurotensin-, and gastrin-immunoreactive cells were detected in the gizzard. These endocrine cells began to appear from 10th d of incubation. Argyrophil cells and GRP-immunoreactive cells in the gizzard were increased with age. Other kinds of immunoreactive cells were found rarely and irregularly, and some of them were found transitory in the embryonic stage.