ENDOGENOUS DOPAMINERGIC ACTIVITY IN CHILD-PUGH-A CIRRHOSIS - POTENTIAL ROLE IN RENAL SODIUM HANDLING AND IN THE MAINTENANCE OF CLINICAL COMPENSATION

Background We studied the main determinants of aldosterone secretion i n a group of 20 patients with biopsy-proven Child-Pugh A cirrhosis wit hout previous ascites or diuretic consumption. Methods We evaluated th e plasma levels of adrenocorticotrophic hormone (ACTH), active renin a nd aldosterone (both supine at 07.00 h and after 30 min of upright pos ture),and active renin and aldosterone responses 30 thin and 60 min af ter the administration of metoclopramide, a dopamine DA(2) antagonist (10 mg e.v.). Nine normal subjects were also submitted to the metoclop ramide stimulation test. Results Compared with control subjects, the p atients showed significantly greater incremental aldosterone responses both 30 min and 60 min after metoclopramide (+30 min: 157.5 +/- 73.3 vs. 83.5 +/- 32.2 pg mL(-1), P < 0.003; +60 min: 142.1 +/- 87.2 vs. 36 .8 +/- 39.0 pg mL(-1), P < 0.001). We found significant positive corre lations between amplitude of aldosterone response 30 min after metoclo pramide and 24-h urinary fractional excretion of sodium (r = 0.61, P < 0.01) and basal morning aldosterone levels (r = 0.69, P < 0.001). Con clusions The higher incremental aldosterone responses observed after m etoclopramide in cirrhotic patients are expressions of increased dopam inergic activity in these patients compared with control subjects. Mor eover, the correlation we found between the degree of dopaminergic act ivity and 24-h urinary fractional excretion of sodium suggests a role for endogenous dopamine as a relevant mediator of natriuresis in cirrh osis, at least in patients with compensated disease.