The endocrine apparatus of the epithelium of the gastric mucosa in the steppe turtle (Testudo horsfieldi)

: Endocrinocytes of stomach mucosal epithelium were studied using light and electron microscopy in steppe turtle (Testudo horsfieldi). Endocrine apparatus of stomach in turtle was shown to retain the pattern characteristic for other representatives of vertebrates. Difference is observed in endocrinocytes localization. The latter are accumulated predominantly in upper and middle regions of glandulae, sometimes being encountered also in surface epithelium. 8 cell types were identified according to size and structure: EC, G, D, D1, A-like, X, ECL and P. Relating to glandular lumen, endocrinocytes are divided into elements of closed (D, D1, A-like, ECL, X, and P) and open types (EC, G). In the latter apico-basal differentiation is expressed in cytoplasmic structure. Endocrinocytes are unevenly distributed throughout the stomach regions. Greatest number is concentrated in pyloric part, EC-cells being the predominant type. EC, ECL-cells and less A-like and D-cells are mostly encountered in fundal part, EC, G and single D and P cells--in pyloric part and, agranular and exo-endocrine cells--in both stomach parts.