Binding of hypoglycaemic sulphonylureas to an artificial phospholipid bilayer.

Hypoglycaemic sulphonylureas bind to multilamellar liposomes formed of egg yolk phosphatidylcholine. In this artificial model, both specific and non-specific components of the binding phenomenon can be characterized by the same criteria as those used in studies performed with natural membranes. The relative ability of distinct sulphonylureas to inhibit the binding of 3H-glibenclamide or 3H-gliquidone to the liposomes parallels their relative potency as insulin secretagogues. It is proposed that the insertion of hypoglycaemic sulphonylureas into the phospholipid domain of the B cell membrane could represent a primary event in the mechanism by which these agents stimulate insulin release.