Glucagon and Blood Sugar

To the Editor: Sherwin et al., in their article (N Engl J Med 294: 455–461, 1976), and Levine, in his editorial (N Engl J Med 294: 494–495, 1976), concude that glucagon exerts a diabetogenic action only when there is insulin deficiency and not in the normal patient. This point of view is not consistent with findings in the glucagonoma syndrome, which is a rare clinical condition characterized by the association of a distinctive cutaneous eruption with a glucagon-secreting islet-cell neoplasm of the pancreas. Typically, these patients exhibit a diabetic glucose tolerance curve presumably related to high circulating glucagon levels.