The mechanisms underlying the unique pharmacodynamics of nateglinide

Nateglinide, a D-phenylalanine derivative, belongs to a new group of insulinotropic agents with rapid onset and short duration of action. These agents have been developed to reduce the risk of hypoglycaemia associated with pharmacological control and to decrease the likelihood of pancreatic beta-cell exhaustion. Nateglinide mediates the release of insulin from beta-cells by binding to the sulphonylurea receptors, which leads to the closure of ATP-sensitive K(+) channels. Increasing evidence from receptor binding, mechanistic and in vitro and in vivo insulin studies indicate unique pharmacodynamic and pharmacokinetic properties with nateglinide that are distinct from those of sulphonylureas. The time required by nateglinide to close beta-cell K(ATP) channels is comparable to that of glyburide but threefold and fivefold faster than repaglinide and glimepiride, respectively. Furthermore, its effects are rapidly reversed with an off-rate at the K(ATP) channel twice as fast as that of glyburide and glimepiride and five times faster than repaglinide. This results in a rapid and short insulin response characteristic of the physiological pattern of post-mealtime insulin release. Internalisation into beta-cells is not required for the action of nateglinide. Given that the kinetic profile of the agent is associated with selective enhancement of early-phase insulin secretion, nateglinide is expected to minimise post-meal hyperglycaemia with minimal propensity for hypoglycaemia.