Effects of α‐adrenoceptor antagonists on clonidine‐induced inhibition of insulin secretion by isolated pancreatic islets

Abstract

1 The effects of clonidine, yohimbine, corynanthine and prazosin on glucose-induced insulin secretion by incubated or perifused mouse pancreatic islets were investigated. 2 Clonidine (0.1 μm) inhibited glucose-induced insulin secretion alone and in the presence of yohimbine (0.1 μm), corynanthine (10 μm) or prazosin (1 μm). 3 In higher concentrations, yohimbine (1–10 μm) antagonized the inhibitory effect of clonidine (0.1 μm) upon glucose-induced insulin secretion by incubated islets and by perifused islets. 4 The results support the view that adrenergic inhibition of insulin secretion is mediated by α₂-adrenoceptors on pancreatic β-cells.