A wealth of evidence shows that nitric oxide can modulate the autoregulation of renal blood flow, the glomerular surface area available for filtration, the glomerulotubular feedback response, and the release of renin. From an integrative point of view, inhibition of nitric oxide synthesis will alter the function of all of these homeostatic mechanisms and impair the pressure-induced natriuresis secondary to increases in intrarenal vascular resistance and tubular sodium reabsorption. These effects, along with an elevation of both total peripheral resistance and vascular tone of the capacitance vessels, are the most likely determinants of the volume-dependent elevation of blood pressure (ie, salt-sensitive hypertension) that occurs during partial inhibition of nitric oxide synthesis. This observation has important physiological and pathologic implications because it shows for the first time that the blockade of a single endogenous vasodilator substance can produce a sustained increase in blood pressure that can be influenced by changes in blood volume. Because of these characteristics, this review emphasizes in particular the characteristics of the nitric oxide synthesis pathway and briefly describes several known methods of increasing the biologic activity of nitric oxide; these methods eventually may be modified and used as therapeutic interventions in humans with deficient nitric oxide synthesis.