<qa>  What is the potential to meet this medical need?Improving the glycaemic control using incretin-based therapies has the potential to meet this medical need. The incretin hormones and their metabolites are however to a large extent excreted by the kidneys and this may lead to problems or benefits! when administered to patients without kidney function or with severely reduced kidney function. The present knowledge about the incretin effect and incretin hormone physiology as well as pharmacokinetics, clinical effects and side effects of GLP-1 analogues in patients with reduced kidney function is limited and the few studies available are predominantly confined to patients with only mild or moderately reduced kidney function. The investigators will explorer basic and pharmacologic aspects in patients with severe reduced kidney function depending on chronic maintenance dialysis treatment. Before any potential treatment can be initiated, the investigators need basic information on how the incretin system is affected by an uraemic milieu. Current and succeeding substudies will provide us with that information. 