GCG and type 1 diabetes mellitus: Although many questions remain unanswered regarding the GLP-1 analogue, Exendin-4 and the renin-inhibitor, Aliskiren, it is evident that treatment with both Exendin-4, and Aliskiren greatly improves the GLP-1 binding affinity at the coronary endothelium level of the type 1 diabetic rat.