Both pre- and postconditioning seem to protect cardiomyocytes during reperfusion therapy. Investigations both ex vivo and in vivo suggest that a gut derived hormone, Glucagon-Like-Peptide-1 (GLP-1), is able to reduce reperfusioninjury after myocardial ischemia. Results from our own laboratory have shown a marked reduction in infarct size when rat hearts in a Langendorf preparation were exposed to the GLP-1 analogue, exendin-4. The investigators want to investigate to what extent this effect can be translated to humans in the setting of acute STEMI treated with primary PCI when evalutaed by cardiac magnetic resonance imaging.