ALDOSTERONE AND RENIN-ANGIOTENSIN RESPONSES TO STIMULI IN PATIENTS WITH TREATED CONGESTIVE HEART-FAILURE

  • 1 January 1976
    • journal article
    • research article
    • Vol. 87  (6) , 1005-1015
Abstract
Aldosterone responses to physiologic doses of known regulatory factors were studied in 8 patients with treated congestive heart failure under standard conditions of electrolyte balance and controlled body posture. The response of plasma aldosterone, plasma renin activity (PRA) and in some instances angiotensin II, to the brief (120 min) i.v. administration of ACTH (1.25 .mu.g .beta.1-24 ACTH in 60 min and 5 .mu.g in 60 min), angiotensin II (30 .mu.g) and K (30 meq), and to 2 h in the upright posture, was measured. The plasma aldosterone increase was greatest in response to ACTH (mean increment 20.8 ng/100 ml) followed by that with upright posture (mean rise 17.1 ng/100 ml), K (mean 6.7 ng/100 ml) and angiotensin II (5.8 ng/100 ml). PRA rose following 2 h of upright posture and fell with angiotensin II infusion, but showed no definite change in response to K or ACTH. A diurnal pattern of PRA, angiotensin II and plasma aldosterone on control days was observed in these patients, with higher prenoon levels falling to a nadir at midnight. The electrolyte and hormone response to administered aldosterone (75 .mu.g over 2 h) was studied in the same patients. During aldosterone infusions, plasma aldosterone increased (increment range 36-110 ng/100 ml), urine Na excretion decreased, but no significant change in urine K excretion or in PRA was observed. Small fluctuations in ACTH secretion, and change in body posture, produce marked effects on plasma aldosterone in patients with controlled congestive heart failure. Aldosterone responses to ACTH in these patients is similar to that observed in normal subjects.