Vasopressin and hypertension in man

Area of Science:

• Endocrinology
• Nephrology
• Cardiovascular Medicine

Background:

• Vasopressin, also known as antidiuretic hormone (ADH), plays a role in regulating blood pressure and fluid balance.
• Its precise role in various forms of human hypertension remains incompletely understood.

Purpose of the Study:

• To investigate the association between circulating vasopressin levels and different types of human hypertension.
• To determine if increased vasopressin levels or sensitivity contribute to elevated blood pressure in hypertensive individuals.

Main Methods:

• Measured plasma vasopressin concentrations in patients with primary hyperaldosteronism, benign essential hypertension, malignant-phase hypertension, and normotensive controls.
• Administered vasopressin infusions to normotensive subjects and patients with essential hypertension to assess pressor sensitivity.
• Examined blood pressure in patients with syndrome of inappropriate ADH excess due to bronchogenic carcinoma, who have chronically elevated vasopressin.

Main Results:

• Circulating vasopressin was lower in primary hyperaldosteronism and benign essential hypertension compared to normotensive subjects.
• Plasma vasopressin levels were significantly increased in malignant-phase hypertension.
• Exogenous vasopressin infusion at levels found in malignant hypertension did not elevate blood pressure in normotensive subjects.
• Patients with essential hypertension showed a slight increase in vasopressin sensitivity, but not enough to explain their high blood pressure.
• Patients with syndrome of inappropriate ADH excess had chronically elevated vasopressin but normal blood pressure.

Conclusions:

• Elevated vasopressin in malignant hypertension is likely a consequence of renal salt and water loss, rather than a cause of the hypertension.
• Vasopressin does not appear to be a significant contributor to the elevated blood pressure in most forms of human hypertension studied.
• Increased pressor sensitivity to vasopressin in hypertension is minimal and insufficient to account for the observed blood pressure elevations.