Sodium excretion, one of the most important homeostatic functions of the body, is modulated by a number of autocrine, paracrine and endocrine factors that act by altering the balance in complex signalling networks in tubular cells. It is probable that most, if not all, integral membrane proteins that transport sodium are regulated by signals from such networks. The activity of the sodium-transporting proteins may be modified by the phosphorylation/dephosphorylation process, or by other means of protein modification. The rate of transport may also be dynamically regulated by other post-translational processes, such as recruitment of the sodium-transporting proteins to the membrane. The identification of the signalling networks that regulate the tubular sodium transporters and of the regulatory sites in these sodium-transporting proteins will bring further insights into the pathophysiology of salt-sensitive hypertension.