Enzymes of the cholinergic system in islets of Langerhans.

Quantitative radiometric assays were employed to measure activities of choline acetyltransferase and acetylcholinesterase in freeze-dried pieces of islets of Langerhans and exocrine tissue from rat pancreas. The activities of both enzymes were about an order of magnitude higher in islets than in exocrine tissue. This difference in activity was found in rats made diabetic with streptozotocin as well as in the controls. Although the enzyme activities in islets from diabetic rats averaged about 30-40% higher than those in islets from control rats, the differences were statistically only marginally significant. Since the islets of diabetic rats are probably much smaller than those of control rats, it is suggested that cholinergic elements associated with pancreatic islets are lost following induction of streptozotocin diabetes.