IMMUNOHISTOCHEMICAL LOCALIZATION OF ENDOCRINE CELLS IN THE GASTROINTESTINAL TRACT OF MT. WUYI CASCADE -FROG (AMOLOPS WUYIENSIS)

Using 7 types of antisera, the regional distribution and distributional density as well as morphological features of endocrine cells in 7 parts of the gastrointestinal track ( GIT)of Mt. Wuyi cascade-frog (Amolops wuyiensis)were investigated by streptavidin-peroxidase(S-P)immune histochemical method. The result showed that four types of gastrointestinal( GI)endocrine cells were identified in the GIT of A.wuyiensis, e. g. 5-hydroxytryptamine ( 5-HT), somatostatin( SS), gastrin( GAS), glucagon (GLU )and immunoreactive ( IR )cells. Substance P ( SP)-, Pancreatic Polypeptide ( PP)-and Insulin( INS)-IR cells were not detected. 5-HT-IR cells distributed throughout the whole GIT at various densities and they were the most predominant cell types in the GIT. SS-IR cellswere detected from cardia to duodenum. GAS-IR cells showed a restricted distribution andwere only demonstrated in the pylorus and duodenum. GLU-IR cellswere only confined to pylorus. In the GIT of A. wuyiensis, the region with the highest degree of cell type heterogeneity was pylorus and all types of endocrine cell along the GIT showed peak density in pylorus as well. The endocrine cells were roundor oval, spindle, shuttle, pyramidor irregularity in shape. And they were mostly found in the gastric glands of the stomach regions and in the epithelium of intestine, and occasionally occurred in lamina propria. The present study showed that some common features on the distributional pattern of the different types of GI endocrine cells were found between A.wuyiensis.and other amphibians, and on the other hand, some species-dependent unique distributional patterns of endocrine cells were also detected in GIT of A.wuyiensis. The results suggested that these characteristics might be related to the GIT physiology and the regulatory characteristics of the GIT of the A.wuyiensis