QUANTITATIVE STUDIES ON ISOLATED PANCREATIC ISLETS OF MAMMALS

Abstract

ABSTRACT Microtitrimetric assays of dipeptidase activity were performed in isolated pancreatic islet tissue from mice. Considerable enzyme activity was found in both the endocrine and exocrine pancreas of normal mice, the enzyme level of the exocrine parenchyma being significantly higher. In obesehyperglycaemic mice with free access to food, isolated islets of Langerhans had a much higher enzyme activity than in normal animals. The increased islet dipeptidase activity in the obese-hyperglycaemic animals may, at least in part, be accounted for by their higher proportion of B cells. The intense insulin synthesis and renewal of B cells in these animals have been considered as alternative explanations. Histochemical staining for leucine aminopeptidase revealed a moderate enzyme reaction in both the endocrine and exocrine pancreatic tissue of normal and obese-hyperglycaemic mice.