Measuring endothelial dysfunction - Reply

We thank Schlaich et al. for their [1] useful comments on our recent paper [2]. We agree that there is no doubt that nitric oxidemediated, endothelium-dependent mechanisms play a key role in alterations of renal haemodynamics induced in humans by systemic L-arginine infusion, which remains an important tool of research in that field [3]. Such changes, however, may not be considered solely as a measure of the endothelial control of kidney circulation, but reflect a more complex sequence of events, including changes in tubulo-glomerular feedback (TGF).