Objective: To assess whether interindividual variation in renal plasma flow or in its response to angiotensin II infusion is associated with interindividual differences in blood pressure in a population-based sample of 287 non-Hispanic whites (143 women and 144 men), aged 20-49.9 years.
Methods: After seven days of eating a high-sodium diet (260 mmol/day), the renal plasma flow was determined by measuring the clearance of p-aminohippurate before and after infusion of 3 ng/kg per min angiotensin II. Multiple linear regression methods were used to assess whether measures of the renal plasma flow and of its response to angiotensin II infusion were predictive of systolic or diastolic blood pressures measured prior to administration of the high-sodium diet, on day 6 of the high-sodium diet, or during the renal clearance procedure on day 7 prior to angiotensin II infusion.
Results: There was some evidence that measures of the renal plasma flow and of its response to angiotensin II infusion during the high-sodium diet were statistically significant predictors of measures of blood pressure in women; there was less evidence for this for blood pressures in men. Interindividual variation in measures of the renal plasma flow and of its response to angiotensin II infusion explained less than 10% of the interindividual variation in any measure of the blood pressure in both sexes.
Conclusion: These results suggest that interindividual variation in renal plasma flow ad in its response to angiotensin II infusion during a high-sodium diet will be of limited utility in elucidating the basis for interindividual differences in blood pressure.