Diabetes and carbohydrate intolerance can occur in pancreatitis. Although one-half of patients with acute pancreatitis will have some evidence of glucose intolerance during their acute illness, few will require insulin administration on either a short- or long-term basis. The diabetes seen in acute pancreatitis is likely due to a combination of factors, including alerted insulin secretion, increased glucagon release, and decreased glucose utilization by the liver and peripheral tissue. Chronic pancreatitis is often associated with diabetes mellitus, with the incidence as high as 70 percent when pancreatic calcification is present. These patients tend to be very sensitive to the effects of insulin and hypoglycemia. This is probably secondary to concurrent hepatic disease, malnutrition, and a relative decrease in glucagon reserves. The diabetes seen in chronic pancreatitis is associated with decreased insulin production. Finally, although the endocrine pancreas may influence the exocrine gland through a portal system, primary diabetes mellitus probably does not result in clinically significant alterations in pancreatic exocrine function.