Ultrastructure of the exocrine pancreas in a sahelian reptile (Varanus exanthematicus) during starvation.

During the sahelian dry season (November to June) the lizard Varanus exanthematicus fasts, and during these 8 months its pancreatic acinar cells lack zymogen granules and show an inactive Golgi body and damaged mitochondria. The main peculiarity can be observed in the granular endoplasmic reticulum (GER): Each acinar cell posesses a great number of GER vesicles (mean diameter 0.15 μm) and a large spheroid GER resulting from either the nesting of some cisternae or the rolling up of a single cisternae on itself. Attention is focused on the possible relationship between this ultrastructure and alteration of protein metabolism.