title: Arterial and venous angiotensin II in normal subjects. Relation to plasma renin activity and plasma aldosterone concentration, and response to posture and volume changes.
abstract: Plasma renin activity, arterial and venous angiotensin II (A II) concentrations, and plasma aldosterone concentration were measured in 16 normal subjects (mean age = 34 years) after 8 hours of recumbency, following 2 hours of ambulation, and again 30 minutes after administration of furosemide intravenously. Measurements were obtained during periods of sodium restriction and again during sodium surfeit. Both arterial and venous A II exhibited a 3-fold increase from low values of 8.8 +/- 2.5 and 8.6 +/- 2.5 pg/ml of plasma, respectively, during recumbency on high sodium intake to values of 23.9 +/- 4.1 and 26.5 +/- 6.2 pg/ml, respectively, following intravenous furosemide during sodium restriction. Corresponding values for aldosterone exhibited a 5-fold rise from 5.6 ng/100 ml to 32.0 ng/100 ml, whereas plasma renin activity (PRA) measured by an in vitro assay exhibited a 20-fold rise from 0.6 +/- 0.2 ng of angiotensin I (AI) generated per ml per hour to 13.1 ng/ml per hour. Despite the disparity in the magnitude of these increases, significant correlations were identified between all four of the measured parameters, indicating a major role of the renin-angiotensin system in regulating aldosterone output in response to volume and posture-related stimuli. Values of arterial and venous immunoreactive A II were closely correlated ( r = +0.72, P less than 0.005), but significant differences were demonstrated between low and high salt periods, suggesting that changes in metabolism of A II in the peripheral circulation may occur during sodium restriction.
mesh_terms: D000328:Adult; D000450:Aldosterone / Q000097:blood* / Q000378:metabolism; D000804:Angiotensin II / Q000097:blood* / Q000378:metabolism; D001158:Arteries; D002986:Clinical Trials as Topic; D004032:Diet; D004039:Diet, Sodium-Restricted; D005110:Extracellular Space; D006801:Humans; D008875:Middle Aged; D009318:Natriuresis; D011187:Posture; D012083:Renin / Q000097:blood*; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride; D014680:Veins
chemical_list: D000804:Angiotensin II; D012965:Sodium Chloride; D000450:Aldosterone; D012964:Sodium; D012083:Renin