title: Reciprocal influence of salt intake on adrenal glomerulosa and renal vascular responses to angiotensin II in normal man.
abstract: The adrenal glomerulosa cell and the renal vasculature respond to similar arterial angiotensin II (A II) levels. We have assessed the effect of decreased sodium intake on their responses to A II in man. Studies were performed in 42 normal subjects in balance on a daily intake of 100 meq potassium and either 200 or 10 meq sodium/day. Renal blood flow was measured with (133)Xe and arterial A II, renin and aldosterone concentrations by radioimmunoassay. A II was infused intravenously (1, 3, or 10 ng/kg/min) for 40-60 min; 14 subjects received graded doses. The A II level increased linearly with dose and plateaued within 3 min; blood pressure and renal vascular resistance showed a similar time-course. Aldosterone rose within 10 and plateaued within 20 min. Dose-response relationships were established between the rate of A II infusion and the adrenal, the renal vascular, and pressor responses. Sodium restriction reduced the pressor (P < 0.01) and the renal vascular response (P < 0.01), but potentiated the adrenal response to A II (P < 0.01). An excellent correlation was found between the plasma A II and aldosterone levels, but the slope of their regression relationship on a high (y = 0.13x + 6) and low salt intake (y = 0.32x + 14) differed significantly (P < 0.0005). Thus, sodium intake reciprocally influences vascular and adrenal responses to A II: salt restriction blunts the vascular response and potentiates the adrenal's, a physiologically important influence in view of aldosterone's role in sodium conservation.
mesh_terms: D000293:Adolescent; D000311:Adrenal Glands / Q000502:physiology*; D000328:Adult; D000450:Aldosterone / Q000097:blood / Q000378:metabolism; D000804:Angiotensin II / Q000494:pharmacology / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D003404:Creatinine / Q000097:blood; D004039:Diet, Sodium-Restricted; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007668:Kidney / Q000098:blood supply / Q000378:metabolism; D008875:Middle Aged; D009130:Muscle, Smooth / Q000502:physiology*; D011188:Potassium / Q000097:blood; D011863:Radioimmunoassay; D012039:Regional Blood Flow / Q000187:drug effects; D012077:Renal Artery / Q000187:drug effects / Q000502:physiology*; D012083:Renin / Q000378:metabolism; D012964:Sodium / Q000097:blood / Q000502:physiology*
chemical_list: D000804:Angiotensin II; D000450:Aldosterone; D012964:Sodium; D003404:Creatinine; D012083:Renin; D011188:Potassium; D006854:Hydrocortisone