Angiotensin II suppression is a major factor permitting excretion of an acute sodium load in humans.
We examined the role of circulating angiotensin II (ANG II) in the excretion of an acute Na+ load in eight healthy subjects given 2 liters 0.9% saline in a placebo-controlled crossover study. On the control day, plasma ANG II decreased to 40-60% of basal values and 35 +/- 9 (SE) mmol of Na+ was excreted in the 5 h after the start of saline infusion. When ANG II was infused to maintain plasma ANG II levels at around basal values (6.6 +/- 1.6 pmol/l), only 7 +/- 8 mmol of Na+ was excreted in the same period (P < 0.05). In a previous similar study in which the fall in aldosterone was prevented by infusion of aldosterone, 16 +/- 16 mmol of Na+ was excreted vs. 36 +/- 16 mmol on the control day in comparable 5-h periods. Suppression of ANG II is one of the major factors permitting the acute increase in Na+ excretion after an intravenous Na+ load. ANG II has direct actions on Na+ excretion in addition to its effects on aldosterone.
Singer
D R
DR
Department of Physiological Medicine, St. George's Hospital Medical School, London, United Kingdom.
Markandu
N D
ND
Morton
J J
JJ
Miller
M A
MA
Sagnella
G A
GA
MacGregor
G A
GA
D000328:Adult; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000037:antagonists & inhibitors* / Q000097:blood / Q000494:pharmacology; D001794:Blood Pressure; D004231:Diuresis; D004311:Double-Blind Method; D004573:Electrolytes / Q000652:urine; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009318:Natriuresis / Q000502:physiology*; D010919:Placebos; D012083:Renin / Q000097:blood; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors
D004573:Electrolytes; D010919:Placebos; D000804:Angiotensin II; D012965:Sodium Chloride; D000450:Aldosterone; D012083:Renin