The aim of the present study is to characterise the hemodynamic effects of FFAs in the kidney. In addition we want to test the hypothesis that FFA-induced changes are mediated via endothelial derived nitric oxide (NO). The results of this study could provide information to what extent elevated FFA-plasma levels contribute to hyperfiltration in the early course of diabetes mellitus. The measurements will be done at baseline and during 4 hour infusion of a triglyceride or placebo infusion, combined with heparin.