ACTH-Mediated Insulin Secretion: Effect of Aminophylline

The effect of theophylline ethylenediamine, aminophylline, on ACTH-mediated insulin secretion was studied in mice. Aminophylline pretreatment markedly increased the magnitude of the plasma insulin rise following ACTH. It did not, however, increase the duration of the ACTH effect nor did it appreciably lower the minimum dose of ACTH which caused insulin release. The dose of aminophylline necessary to augment ACTH-mediated insulin secretion did not inhibit pancreatic protein synthesis as estimated by 14C-L-leucine incorporation. The aminophylline augmentation of ACTH-mediated insulin release occurred in both intact and adrenalectomized animals. Aminophylline also augmented glucagon and glucose-mediated insulin secretion. The data raise the question of the possible role of the adenyl cyclase system in the mechanism of ACTH action on the pancreatic β cell. (Endocrinology 81 : 558, 1967)