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[Circulating inhibitor of the Na+-K+ pump in essential hypertension. Physiological and pharmacological variations]
Insights
A circulating sodium (Na+) pump inhibitor, possibly linked to digitalis, was found in higher levels in individuals with essential hypertension and high sodium intake. Lower levels were observed in hypertensive patients on diuretics and those with kidney failure.
Area of Science:
- Cardiovascular Physiology
- Renal Physiology
- Endocrinology
Background:
- Circulating factors influencing sodium (Na+) pump activity are implicated in blood pressure regulation.
- Digitalis-like compounds have been proposed as endogenous regulators of cardiovascular function.
Purpose of the Study:
- To assess the presence and levels of a circulating Na+ pump inhibitor in human subjects.
- To investigate the association between inhibitor levels and conditions such as essential hypertension, sodium intake, and renal function.
Main Methods:
- Deproteinized plasma from 112 subjects was analyzed for its effects on ouabain binding to erythrocytes.
- Na+-K+-ATPase activity inhibition was measured to quantify the circulating inhibitor.
Main Results:
- High levels of the inhibitor, exhibiting digitalis-like properties, correlated with essential hypertension, hypertensive heredity, beta-blocker treatment, and high sodium intake.
- Low inhibitor levels were detected in hypertensive patients using diuretics, individuals with chronic renal failure, and normotensive controls.
Conclusions:
- The circulating Na+ pump inhibitor may play a role in sodium balance regulation.
- These findings suggest a potential involvement of this inhibitor in the pathophysiology of hypertension.
Abstract:
The presence of a circulating Na+ pump inhibitor has been assessed in 112 subjects by studying the effects of deproteinized plasma on ouabain binding to erythrocytes and/or inhibition of Na+-K+-ATPase activity. High levels of an inhibitor possessing some digitalis-like properties, were associated with essential hypertension, hypertensive heredity, treatment of hypertension with beta-blocking agents and high sodium intake. Low levels were found in hypertensives on diuretics, patients with chronic renal failure and normotensive controls. These observations are consistent with a possible role of this circulating inhibitor in the control of sodium balance and in hypertension.