Plasma pancreatic glucagon response to blood glucose in experimental pancreatolithiasis in dogs.

In an attempt to study pancreatic A cell function at an early stage of pancreatic diabetes secondary to chronic pancreatitis, both intravenous glucose (0.5 g/kg) and insulin (0.5 U/kg) tolerance tests were performed on seven dogs with pancreatolithiasis and seven normal control dogs. Experimental pancreatolithiasis was produced 12 months after incomplete ligation of the greater pancreatic duct. Impaired glucose tolerance and reduced plasma insulin response to an intravenous glucose load were observed in the calcified group. Pancreatic release of glucagon to insulin-induced hypoglycaemia was diminished, but suppressive response of the hormone to glucose-induced hyperglycaemia was well preserved. These data suggest that the A cell response to hypoglycaemia may be impaired earlier than that to hyperglycaemia in pancreatic diabetes secondary to pancreatolithiasis.