PANCREATIC ALPHA-CELL AND BETA-CELL FUNCTION IN PHEOCHROMOCYTOMA

Arginine infusion tests were carried out in seven patients with pheochromocytoma before and after extirpation of the tumors in order to evaluate pancreatic islet α- and β-cell function during the state of endogenous catecholamine excess. Six of the patients had glucose intolerance; one did not. Preoperatively, the pancreatic glucagon response was suppressed, while the insulin response was comparable to that in normal control subjects. Plasma glucose levels decreased rapidly after the beginning of arginine infusion in all patients. These changes during the infusion were evident in the one patient without glucose intolerance. Postoperatively, the glucagon response and plasma glucose changes were normalized. In addition to the obvious suppression of pancreatic α-cell function in our patients with pheochromocytoma, it seems likely that pancreatic β-cell function also was suppressed; there was no enhancement of the insulin response to arginine during the period of chronic hyperglycemia, a situation in which a synergistic effect between glucose and arginine might be expected. © 1979 by The Endocrine Society.