The activities of the lysosomal enzymes acid amyloglucosidase and β-glucuronidase
were assayed in isolated pancreatic islets and liver tissue from three different strains
of mice. It was observed that acid amyloglucosidase activity in islets isolated from
the CBA-strain and the C-57 strain was only 44% and 36% respectively of the activity
recorded in the NMRI-strain. β-Glucuronidase activity displayed a similar pattern.
In liver tissue the activities of the two lysosomal enzymes displayed a different
pattern. The highest activities of acid amyloglucosidase and β--glucuronidase in the
liver were observed in the C-57 strain while the other two strains showed slightly
lower activities. There was no difference between the three strains with regard to
basal plasma insulin levels and thus no apparent relation to the activities of the
lysosomal enzymes in the islets. However, the insulin releasing capacity in the three
different strains following an intravenous injection of a maximal dose of the sulphonylurea
compound, glibenclamide, roughly correlated with islet amyloglucosidase activity while
a similar stimulation by the β-adrenergic agonist L-isopropylnoradrenaline (L-IPNA)
elicited an insulin response of equal magnitude in all three strains. It is suggested
that acute sulphonylureastimulated insulin release is dependent on islet amyloglucosidase
activity while β-adrenergic stimulation of insulin release is independent of the activity
of this enzyme.
Acid Amyloglucosidase - β-Glucuronidase - Isolated Pancreatic Islets - Liver - Plasma
Insulin - Glibenclamide - L-lsopropylnoradrenaline - NMRI Mice - C-57 Mice - CBA Mice
