Mitochondries ge´antes dans les cellules A du pancre´as d'un varan:Varanus niloticus

Pancreatic A cells of the lizardVaranus niloticus are characterized by the presence of two types of mitochondria: (a) normal, small mitochondria (about 0.4 × 1μm), and (b) giant mitochondria, measuring up to 9 μm in length and 1 μm in diameter. Giant mitochondria show various shapes. Their matrix is filled with tubules, filaments, and dense granules. Transverse sections of tubules are polygonal in shape and about 20 nm in diameter. They are grouped in bundles. The filaments, about 9–10 nm in diameter, are arranged in parallel layers crossing each other at a 57° angle. In a closely related species,Varanus exanthematicus, pancreatic A cells do not show these peculiar features.