title: Sodium kinetics in white and black normotensive subjects: possible relevance to salt-sensitive hypertension.
abstract: The hypothesis that sodium (Na) kinetics are not a first order process was tested. Twelve normotensive white and 12 normotensive black men were given 10, 200, and 400 mmol/d Na as the chloride salt for 7 days in random order. All urine made was collected. No effect of Na intake on blood pressure was identified in either whites or blacks. The half-life (T1/2) with decreasing Na intake to 10 mmol/d was 1.08 days in whites and 1.65 days in blacks (p = not significant [NS]). With increasing Na intake, T1/2 increased in both whites and blacks; at the 400 mmol/d intake, the T1/2 for whites was 2.88 days and for blacks was 5.81 days (p < 0.05). At that intake, whites accumulated 385 +/- 153 mmol compared with 909 +/- 153 mmol for blacks (p < 0.05). The data showed that T1/2 increases with increasing Na intake and is, therefore, dose-dependent or "zero" order. The effect of dose is more prominent in blacks than in whites; blacks accumulate more Na with increasing Na intake than whites. These data may have relevance for the pathogenesis of salt-sensitive hypertension in blacks.
authors.affiliation: Department of Internal Medicine, University of Louisville, Kentucky.
authors.forename: M E
authors.initials: ME
authors.lastname: Brier
authors.forename: F C
authors.initials: FC
authors.lastname: Luft
mesh_terms: D000328:Adult; D044383:Black People; D005260:Female; D006801:Humans; D006973:Hypertension / Q000208:ethnology / Q000209:etiology*; D007700:Kinetics; D008297:Male; D012964:Sodium / Q000378:metabolism*; D012982:Sodium, Dietary / Q000008:administration & dosage; D044465:White People
chemical_list: D012982:Sodium, Dietary; D012964:Sodium