Natriuresis induced by mild hypernatremia in humans.
The hypothesis that increases in plasma sodium induce natriuresis independently of changes in body fluid volume was tested in six slightly dehydrated seated subjects on controlled sodium intake (150 mmol/day). NaCl (3.85 mmol/kg) was infused intravenously over 90 min as isotonic (Iso) or as hypertonic saline (Hyper, 855 mmol/l). After Hyper, plasma sodium increased by 3% (142.0 +/- 0.6 to 146.2 +/- 0.5 mmol/l). During Iso a small decrease occurred (142.3 +/- 0.6 to 140.3 +/- 0.7 mmol/l). Iso increased estimates of plasma volume significantly more than Hyper. However, renal sodium excretion increased significantly more with Hyper (291 +/- 25 vs. 199 +/- 24 micromol/min). This excess was not mediated by arterial pressure, which actually decreased slightly. Creatinine clearance did not change measurably. Plasma renin activity, ANG II, and aldosterone decreased very similarly in Iso and Hyper. Plasma atrial natriuretic peptide remained unchanged, whereas plasma vasopressin increased with Hyper (1.4 +/- 0.4 to 3.1 +/- 0.5 pg/ml) and decreased (1.3 +/- 0.4 to 0.6 +/- 0.1 pg/ml) after Iso. In conclusion, the natriuretic response to Hyper was 50% larger than to Iso, indicating that renal sodium excretion may be determined partly by plasma sodium concentration. The mechanism is uncertain but appears independent of changes in blood pressure, glomerular filtration rate, the renin system, and atrial natriuretic peptide.
Andersen
Lars Juel
LJ
Department of Medical Physiology, Panum Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark.
Andersen
Jens Lundbaek
JL
Pump
Bettina
B
Bie
Peter
P
D000328:Adult; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000097:blood; D001127:Arginine Vasopressin / Q000097:blood; D009320:Atrial Natriuretic Factor / Q000097:blood; D003681:Dehydration / Q000097:blood / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006955:Hypernatremia / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology; D007262:Infusions, Intravenous; D007552:Isotonic Solutions / Q000008:administration & dosage; D008297:Male; D009318:Natriuresis / Q000187:drug effects / Q000502:physiology*; D009994:Osmolar Concentration; D010953:Plasma Volume / Q000187:drug effects / Q000502:physiology; D012016:Reference Values; D012083:Renin / Q000097:blood; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage; D012964:Sodium / Q000097:blood / Q000652:urine; D014868:Water Deprivation
D007552:Isotonic Solutions; D012462:Saline Solution, Hypertonic; D000804:Angiotensin II; D001127:Arginine Vasopressin; D000450:Aldosterone; D009320:Atrial Natriuretic Factor; D012964:Sodium; D012083:Renin