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

Abstract

Glucose-6-phosphatase (G-6-Pase) and acid phosphatase (Ac-Pase) activities were followed histochemically in hyperfunctioning rabbit pancreatic [beta]-cells in cortisone diabetes and after administration of hypoglycemic sulfonylureas. Cortisone diabetic rabbit pancreas with [beta]-cell degranulation and glycogenic vacuolization of ductules and [beta]-cells showed no definite changes in [beta]-cell Ac-Pase or G-6-Pase activity. Hypoglycemic sulfonylureas administered over a period adequate to degranulate [beta]-cells, seemed to diminish their G-6-Pase content without effecting Ac-Pase. Although [beta]-cell degranulation was, in each of these instances, indicative of increased insulin output, lack of alteration of histochemically demonstrable [beta]-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 [beta]-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.