The present invention relates to a novel use of benzazepine-N-acetic acid derivatives which contain an oxo-group in the α-position to the nitrogen atom and are substituted in position 3 by a 1- (carboxyalkyl)cyclopentylcarbonylamino radical, and/or of their salts and biolabile esters, and/or of physiologically acceptable solvates thereof, in larger mammals and particularly in humans, preferably human patients having diabetes, and to the production of pharmaceutical compositions and products suitable for the novel treatment. The invention particularly relates to the treatment and/or prophylaxis of renal dysfunction, disease or disorder, preferably in diabetic patients, but in a broader sense also in patients with syndrome X or in particular in patients with a renal dysfunction, disease and /or disorder, which patients are in addition hypertensive, obese, hyperglycemic and/or subject to metabolic disorder.