Glycogen accumulation in cultured tumoral or normal pancreatic islet and acinar cells

Tumoral pancreatic islet cells of either the RINm5F or INS-1 cell lines, wh en cultured in the presence of 30.0 mM D-glucose, accumulate about 50 times more glycogen than tumoral pancreatic acinar cells of the AR42J line cultu red under the same experimental conditions. Expressed per nl of intracellul ar water, the glycogen content of the RINm5F or INS-1 cells is even higher than that found in rat pancreatic islets also cultured under the same exper imental conditions. Moreover, at variance with normal islet cells, tumoral islet cells do not require to be exposed to a high concentration of D-gluco se to accumulate large amounts of glycogen. Based on these findings, it is proposed that the labelling of the glycogen pool, e.g. by C-11-labelled D-g lucose or 2-deoxy-2-[F-18]fluoro-D-glucose, may allow identification and lo calization of insulinomas in the pancreatic gland by a non-invasive imaging procedure.