Tinctorial, immunocytochemical and ultrastructural characterizations of the endocrine cell types of the pancreas of the soft-shelled turtle, Lissemys punctata punctata (Bonnoterre) (Reptilia: Chelonia)

Abstract

The objective of the present study was to identify the cell types of the endocrine pancreas by tinctorial, immunocytochemical and ultrastructural characteristics in Lissemys punctata punctata turtles. (a) B-cells were identified by fine light purple cytoplasmic granules tinctorially, insulin antibody reaction (brown colour), and mitochondrial zone with crystalline-like secretory granules ultrastructurally. (b) A-cells were characterized by very fine orangeophilic granules tinctorially, glucagon antibody reaction (bluish colour), and rough endoplasmic reticular (RER) and mitochondrial zones with larger secretory granules ultrastructurally. Other cell types were identified from ultrastructural characteristics. (c) D-cells had RER zone with clustered large secretory granules. (d) PP-cells showed fusiform shape with tapering ends, RER and mitochondrial zones, and small secretory granules. (e) Vth-cell type was characterized by triangular shape with mitochondrial zone and clustered secretory granules. (f) VIth-cell type was identified by pyriform shape, mitochondrial zone, and least population of clustered secretory granules. We conclude that the occurrence of several types of pancreatic endocrine cells may be related to the adaptation of Lissemys turtles.

Keywords:

• Pancreatic endocrine cell types
• tinctorial characters
• immunohistochemistry
• ultrastructure
• turtle

Acknowledgements

Insulin and glucagon antibodies were donated by Professor Debi Prasad Sarkar, Department of Biochemistry, University of Delhi. Transmission electron micrographic work was carried out in the laboratory of Dr T. C. Nag, AIIMS, New Delhi. Dr. Shibsankar Roy, IICB, assisted in immunocytochemical technique and Gautam Ghosh, Department of Zoology, Midnapore College, helped in colour photography. Dr. Tapan Dutta, Assistant Professor of Life Science, Panskura Banamali College, East Midnapore, West Bengal, India, prepared computerised histograms and photoplates of the manuscript.