Development of the embryonic liver and pancreas of the Chinese softshell turtle Trionyx sinensis.

The research on hatching ecology of the Chinese softshell turtle Trionyx sinensis has essential guiding roles to clarify the physiological and ecological mechanism of reptile evolution. The aim of this study is to describe the histological changes, differentiation, and maturation of some functional cells during the genesis and development of the liver and pancreas of the Chinese softshell turtle T. sinensis. Softshell turtle eggs were incubated under artificial conditions and hatched within 41-45 days. Hematoxylin and eosin-stained embryonic pancreas and liver were examined at various time points from 2 to 31 days and compared with that of other reptiles, amphibians, fishes, and birds in the literature. Immunohistochemical assay for glucagon and insulin was performed on paraformaldehyde-fixed embryos to identify functional cells in the pancreas. Pancreatic endocrine cells of T. sinensis have secretory ability at day 26 of embryonic development, and the dispersed pancreatic endocrine cells may be the result of the incomplete pancreatic development.