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.