Salt-sensitive Hypertension
Conditions
Keywords
Salt, Balance, Renin Angiotensin System, Fenoldopam\blood Pressure, Sodium
Brief summary
The kidney plays a crucial role in maintaining salt balance by two opposing physiological mechanisms: the renal dopaminergic system which enhances salt excretion and the renin-angiotensin system (RAS) which causes salt retention. Salt-sensitive hypertension occurs when this balance is altered or abnormal. We hypothesized that this balance is influenced by salt intake: therefore dietary salt affects the natriuretic response to the renal dopaminergic agonist Fenoldopam, and the Angiotensin Converting Enzyme inhibitor, Enalapril. In this trial we study normal salt balance mechanisms in salt resistant adults with normal blood pressure.
Detailed description
Eight adults of both genders and all races were studied in this double blind placebo controlled cross over study with randomization of the order of interventions. After 5 days each on low salt (about 1 gram/day) and high salt (about 6 grams/day)diet, with a washout period of at least four weeks in between, every subject was treated with Enalapril and Placebo on two consecutive days, followed by a Fenoldopam infusion for three hours, during which natriuresis and renal function testing were performed.
Interventions
DRUGFenoldopam
Intravenous infusion at 0.5 mics/Kg/min for three hours
Sponsors
University of Virginia
Georgetown University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
* Volunteers * Healthy * Normal Blood Pressure
Exclusion criteria
* Renal Impairment * Obesity * Salt sensitive increase in blood pressure
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Urinary sodium excretion | During the trial: a 3 hour fenoldopam infusion | All subjects received placebo/enalapril in a randomized counterbalanced fashion in both phases. Phase 1 was on low salt, while Phase 2 was on high salt. All subjects received a 3 hour fenoldopam infusion, during which time urinary sodium excretion was measured as the primary outcome bvariable. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Renal Plasma Flow | During 3 hour fenoldopam infusion | In order to explain physiologically the effects of fenoldopam on urinary sodium excretion on high and low salt diet, with and wothout enalapril, renal plasma flow was measured during the infusion using PAH clearance |
Countries
United States
Outcome results
None listed