Abstract
Islets of Langerhans isolated from streptozotocin-treated guinea-pigs contain a majority
of glucagon-producing A2-cells. These islets have been used to study the activities of adenylate cyclase and
protein kinase in the pancreatic A2-cells. Both enzymes were present in the A2-cell richt islets and possessed general characteristics similar to those of B-cell
rich islet tissue. The A2-cell adenylate cyclase was stimulated by adrenaline, and the protein kinase was stimulated
in the presence of adrenaline and theophylline, agents which also increased glucagon
release from guinea-pig islets. A major difference was therefore noted between the
responses of the A2-cells and B-cells to adrenaline, since adrenaline decreases the activity of adenylate
cyclase and protein kinase in the B-cells. Nevertheless, both cell types responded
to an elevation of adenylate cyclase and protein kinase activity with an increase
in hormone secretion.
Key words
Adenylate Cyclase - Protein Kinase - A2-Cell - Islets of Langerhans - Glucagon - Adrenaline
