[Effects of dopamine infusion on the release of atrial natriuretic factor]

We evaluated the effects of dopamine infusion (1.5 micrograms/Kg/min for 60 min) on secretion of atrial natriuretic factor before raised diuresis could affect extracellular fluid volume and hence peptide release. We investigated ten healthy subjects without cardiovascular, renal or endocrine disease and ten patients with congestive heart failure (New York Heart Association Classes III and IV). The study protocol required four 30 minute clearance periods: 1st basal, 2nd during placebo, 3rd and 4th during dopamine infusion. We measured diuresis, natriuresis, glomerular filtration rate, blood pressure, heart rate, central venous pressure and plasma concentrations of atrial natriuretic factor, noradrenaline, renin activity, aldosterone and antidiuretic hormone. Blood samples were drawn at the midpoint of each clearance period after measuring blood pressure, heart rate and central venous pressure. Atrial natriuretic factor was determined by radioimmunoassay after chromatographic extraction, noradrenaline was measured fluorometrically while plasma renin activity, aldosterone and antidiuretic hormone concentrations were obtained by radioimmunoassay. During dopamine infusion plasma atrial natriuretic factor plasma levels were significantly raised in healthy subjects while high basal values of the peptide in patients with congestive heart failure were significantly reduced; this trend was also evident for noradrenaline levels in both groups. Plasma renin activity, aldosterone and antidiuretic hormone values remained unchanged in healthy subjects, but plasma renin activity and aldosterone levels dropped significantly in congestive heart failure patients. Diuresis, natriuresis and glomerular filtration rate were significantly increased while blood pressure, heart rate and central venous pressure remained unchanged in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)