The Islets of Langerhans of the Pancreas of Macropodid Marsupials: a Comparison With Eutherian Species.

Abstract

The islets of Langerhans were studied in the pancreas of the red kangaroo, grey kangaroo and euro, and compared with those of the brush-tailed possum and of various eutherian species. The mean (± SE) percentages of insulin-producing (B) cells in the islets of the species studied were: red kangaroo, 8.1kO.58; grey kangaroo, l5.9 ± 0.74; euro, 9.9 ± 0.82; possum, 52.7 ± 0.84; sheep, 12.5 ± 1.16; cattle, 74.6 ± 0.58; rabbit 76.9 ± 0.83; rat, 66.9 ± 0.43. The low proportions of B cells in the islets of the kangaroos and sheep were accompanied by high proportions of glucagon-producing cells and agranular cells. The size of the islets, estimated from the number of cells per islet, was smallest in the sheep and largest in cattle (23.5 ± 1.27 and 66.3 ± 4.75 cells per islet respectively). However, the total number of islet cells per unit area of pancreas was significantly different only between euros (432 ± 28.8) and cattle (848 ± 100.7). Significant, negative correlations were found between pancreas weight as a percentage of live body weight and live body weight in the three species of kangaroo. The data for all species subscribed to the hypothesis that, in mammals, as body size increase the relative mass of the pancreas decreases.