Abnormalities in the endothelial L-arginine/NO signalling pathway are also dependent of several regulatory mechanisms, including up-regulation caused by activation of A2A-adenosine receptors in the micro- and macrovasculature of the human placenta in GDM (and perhaps in OP) due to accumulation of extracellular adenosine resulting from reduced hENT expression and activity. Here, ADORA2A is linked to gestational diabetes.