Patients with essential hypertension have an exaggerated natriuretic response to the dopamine pro-drug glutamyl-dopa

The relatively kidney-specific dopamine pro-drug, gamma-L-glutamyl-L-dopa (gludopa) was administered to eight normal subjects and eight patients with essential hypertension, control studies being provided by the infusion of saline on a separate occasion. There was a more marked natriuresis in the hypertensives than in the normal subjects, even though, in contrast to the normals, the hypertensives showed no significant change in effective renal plasma flow (ERPF) or glomerular filtration rate (GFR). A significant fall in plasma renin activity (PRA) occurred in both groups. These observations suggest that a part of the dopamine-induced natriuresis is due to stimulation of tubular receptors, and that there is up-regulation of these receptors in essential hypertension.