Individual responses to alterations in salt intake vary widely. While salt has no effect on blood pressure in some people, it may substantially increase pressure in others. The reason why this difference exists is not very clear yet but many observations point towards the kidney as an important mediator. The adaptation in urinary output of sodium after a salt challenge (increase or decrease) also is not uniform. It is thought that the renin-angiotensin system may play an important role in determining how much sodium the body expels or retains after salt intake is suddenly reduced or augmented. Recent data suggest that the peptide Ang (1-7) and the endogenous nitric oxide inhibitor asymmetric dimethylarginine could be critically involved in the regulation of the renal response to altered salt intake.