HISTOCHEMICAL STUDIES ON GLUCOSE-6-PHOSPHATASE, ADENOSINE TRIPHOSPHATASE AND AMYLO PHOSPHORYLASE IN THE PANCREATIC ISLETS OF NORMAL AND OBESE-HYPERGLYCAEMIC MICE

Abstract

ABSTRACT Histochemical methods for the detection of glucose-6-phosphatase (G-6-Pase), adenosine triphosphatase (ATPase) and amylo phosphorylase were applied to the islets of Langerhans in mice with hereditary obesity and hyperglycaemia (AO-mice) and in their lean litter mates (AN-mice). While the G-6-Pase activity was high in the hyperactive B cells of the AO-mice, it was only moderate in the AN-mice. In both types of mice ATP-hydrolyzing enzymes were observed in the islet capillaries and periinsular connective tissue, while the reaction in the islet cells was negative. From a study of the substrate specificity it was found that the enzyme activity was not dependent on specific ATPase, but probably mainly on less specific polyphosphatases. The reaction for amylo phosphorylase was negative in the islets of both the AN- and the AO-mice. The high G-6-Pase activity in the islets of the AO-mice is discussed in the light of the hypothesis that the activity of this enzyme represents an essential controlling factor in the insulin output of the B-cells.