Introduction
The incretin hormone, GIP, is responsible for augmenting postprandial insulin release and regulation of β-cell mass. The advent of newly-developed GIP analogues, which have been demonstrated to restore glycaemic control in animal models of type 2 diabetes mellitus (T2DM), suggest that GIP-based therapies may now realise their long-held promise for the treatment of T2DM. Interestingly, we have recently shown that GIP may also exert vasodilatory actions which appear to be mediated via endothelium-dependent NO production. This may be particularly relevant to T2DM as over 60 % of associated mortality is attributable to cardiovascular disease related to dysregulation of endothelial NO homeostasis. An improved understanding of the mechanisms underlying GIP's recently-described vascular actions is clearly important. The aim of this study was therefore to dissect the precise mechanisms involved in GIP-mediated endothelial NO signalling.