INCREASED URINARY DOPAMINE EXCRETION IN YOUNG-PATIENTS WITH ESSENTIAL-HYPERTENSION

The evidence that some older patients with essential hypertension have low urinary dopamine excretion has brought into question the levels o f urinary dopamine and plasma dopa, the major source of urinary dopami ne, in young patients with essential hypertension. Twentyfour-hour uri ne sodium, creatinine, dopamine and noradrenaline and plasma dopa were evaluated in 48 patients with essential hypertension aged 18 to 27 ye ars and 25 normotensive subjects. In comparison with age-matched normo tensive subjects, the hypertensive patients had higher urinary dopamin e (1920 +/- 80 vs 1520 +/- 130 nmol/day, p < 0.01) and noradrenaline ( 216 +/- 11 vs 179 +/- 12 nmol/day, p < 0.05) excretion. There was a si gnificant correlation between urinary dopamine and noradrenaline excre tion. There was no difference in plasma dopa levels between normotensi ve and hypertensive subjects. These results suggest that the elevated conversion of dopa to dopamine in the kidney is leading to increased u rinary dopamine excretion in young patients with essential hypertensio n.