Stimulation of endothelial nitric oxide synthase by proinsulin C-peptide

• Published in: Nitric oxide 2003-09, Vol.9 (2), p.95-102
• Main Authors: Wallerath, Thomas, Kunt, Thomas, Forst, Thomas, Closs, Ellen I, Lehmann, Ralf, Flohr, Thomas, Gabriel, Matthias, Schäfer, Dirk, Göpfert, Andrea, Pfützner, Andreas, Beyer, Jürgen, Förstermann, Ulrich
• Format: Article
• Language: English
• Subjects: Aniline Compounds - chemistry; Animals; Blotting, Western; C-peptide; C-Peptide - pharmacology; Ca 2+ influx; Calcium - metabolism; Cattle; Cyclic GMP - biosynthesis; Cyclic GMP - metabolism; Endothelial Cells - drug effects; Endothelial Cells - enzymology; Endothelial Cells - metabolism; Endothelial nitric oxide synthase; Enzyme Inhibitors - pharmacology; Fluorescent Dyes; Humans; Microscopy, Fluorescence; Nitric Oxide - metabolism; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase Type III; Nitroarginine - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; RNA - chemistry; RNA - genetics; Xanthenes - chemistry
• ISSN: 1089-8603; 1089-8611
• DOI: 10.1016/j.niox.2003.08.004

There is increasing evidence for biological functions of human C-peptide. Recently, we have described that proinsulin C-peptide increases nutritive capillary blood flow and restores erythrocyte deformability in type 1 diabetic patients, whereas it has no such effect in non-diabetic subjects. The aim of the current study was to elucidate cellular mechanisms of this vasodilator effect in vitro by measuring the nitric oxide (NO)-mediated increase of cGMP production in a RFL-6 reporter cell assay and by demonstrating endothelial calcium influx with the Fluo-3 technique. C-peptide increased the release of NO from endothelial NO synthase (eNOS) in bovine aortic endothelial cells in a concentration- and time-dependent manner. At physiological concentrations of C-peptide, endothelial NO production was more than doubled (208 ± 12% vs control; p