Potassium accelerates urinary sodium excretion during salt loading without stimulating atrial natriuretic polypeptide...

Area of Science:

• Nephrology
• Cardiovascular Physiology
• Endocrinology

Background:

• High salt intake can lead to fluid retention and hypertension.
• Potassium (K) plays a role in regulating sodium (Na) balance.
• Atrial natriuretic polypeptide (ANP) is involved in cardiovascular homeostasis.

Purpose of the Study:

• To investigate the effects of potassium supplementation on urinary sodium excretion and ANP secretion during salt loading in healthy individuals.
• To assess the impact of potassium on volume expansion and norepinephrine levels.

Main Methods:

• 12 healthy salt-resistant normotensive subjects participated in a controlled metabolic ward study.
• Subjects received either potassium (K) supplementation or a placebo during a high salt intake period (350 mEq/day).
• Urinary volume, sodium excretion, body weight, hematocrit, plasma norepinephrine, and plasma ANP were measured.

Main Results:

• Potassium supplementation significantly increased urinary volume and sodium excretion on the first day of high salt intake.
• Potassium-supplemented group showed less body weight gain and a smaller decrease in hematocrit compared to the control group.
• Plasma norepinephrine decreased less in the potassium group, and ANP increased later compared to controls.

Conclusions:

• Potassium supplementation accelerates diuresis and natriuresis, partially suppressing salt-induced volume expansion.
• The enhanced sodium excretion with potassium is not mediated by increased atrial natriuretic polypeptide (ANP).
• Potassium supplementation may offer a protective mechanism against excessive salt-induced fluid retention.