 The aim of this study is to ascertain whether a stable ratio between the blood glucose concentration and the glucose levels at the tissue site of insulin infusion exists when this tissue site is exposed to variable insulin infusion rates. To achieve this, microdialysis and microperfusion probes are applied in healthy and type 1 diabetic subjects to perform insulin delivery and glucose sampling at the same adipose tissue site during euglycemic clamps and oral glucose tolerance tests. 