Variation in plasma glucose and pancreatic beta cells in the turtle, Lissemys punctata (order : Chelonia; family : Trionychidae)

The present study relates to the determination of the plasma glucose level and volumetric analysis of beta cells in pancreatic islets of the soft-shelled turtle Lissemys punctata during different phases of its reproductive cycle. Reproductive events play a vital role in influencing the plasma glucose level and beta-cell behaviour in the pancreatic islets. The colour of the pancreas is either yellowish or pinkish, depending on endocrine activity. Islets are present throughout the gland and range from individual cells to small or large clumps, depending on the seasonal cycle. Splenic islets are dense with more blood capillaries and nerve innervations irrespective of sex and season. The endocrine cell mass forms irregular patches without connective tissue capsule. beta cells occupy the inner region of the islets, being surrounded by other cell types. Lissemys punctata exhibits higher beta-cell activity during hibernation. Most insulin-secreting cells acquire a larger size during the regressive period. An analysis indicates that beta cells outnumber the non-beta endocrine cell mass in both number and per cent volume. There is negative correlation between islet mass and animal weight. Between the periods of reproductive cycles, a difference exists with respect to fasting plasma glucose and beta-cell volume