Acid and Glucose-6-Phosphatase Activity of Pancreatic B Cells after Cortisone and Sulfonylureas. ∗

Summary

Glucose-6-phosphatase (G-6-Pase) and acid phosphatase (Ac-Pase) activities have been followed histochemically in hyperfunctioning rabbit pancreatic B cells in cortisone diabetes and after administration of hypoglycemic sulfonylureas. Cortisone diabetic rabbit pancreas with B cell degranulation and glycogenic vacuolization of ductules and B cells showed no definite changes in B cell Ac-Pase or G-6-Pase activity. Hypoglycemic sulfonylureas administered over period adequate to degranulate B cells, seemed to diminish their G-6-Pase content without effecting Ac-Pase. Although B cell degranulation was, in each of these instances, indicative of increased insulin output, lack of alteration of histochemically demonstrable B cell Ac-Pase activity was not considered to be at variance with the view that this enzyme may be important for insulin synthesis. Inhibition of B cell G-6-Pase activity by chronic sulfonylurea administration could be the mechanism of pancreatic action of these drugs. However, the alternative explanation that reduced G-6-Pase activity was a secondary adaptive response cannot be entirely excluded.