Subpressor doses of angiotensin II do not increase albumin excretion in humans.
The objective of our study was to evaluate the effects of subpressor doses of angiotensin II and mild physical stress on renal hemodynamics and urinary albumin excretion (UAE) in a group of young patients with essential hypertension compared to normotensive subjects. Eleven patients (26 +/- 6 years) and ten healthy control persons (25 +/- 2 years) were enrolled in the study. Secondary forms of hypertension had been excluded. Angiotensin II was infused at a dose of 0.3 and 1.0 ng/kg/min and physical stress testing was done with a cycle ergometer (50 W at 10 min for hypertensives, 100 W at 10 min for normotensives). Renal hemodynamics were assessed by clearance techniques (continuous insulin and p-aminohippurate clearance). Mean arterial pressure (MAP) and UAE were significantly higher in the hypertensive group than in normotensive control persons at any time of measurement. There was no significant increase in MAP or UAE under angiotensin II infusion either in the hypertensive group or in the normotensive group. MAP increased significantly under physical stress in the normotensive group only (83 +/- 7 mmHg baseline vs. 108 +/- mmHg during physical stress, p < 0.05). Angiotensin II infusion resulted in a significant change concerning renal hemodynamics in the hypertensive group only. The filtration fraction increased (18 +/- 3% baseline vs. 25 +/- 7% under infusion of 1.0 ng/kg/min angiotensin II, p < 0.05) due to a decline in ERPF and an increase in GFR in the hypertensive group. The amount of UAE correlated with the magnitude of the MAP in both groups. No correlation was found between renal hemodynamic parameters and the UAE. A significant correlation was found between the norepinephrine levels and the UAE in the control group. We could not demonstrate an albuminuric effect of subpressor doses of angiotensin II in normotensive or hypertensive subjects despite its well known effects on renal hemodynamics with an increase of the filtration fraction. These data provide evidence against a predominant role of angiotensin II and renal hemodynamics concerning the elevated urinary albumin excretion in young patients with arterial hypertension.
Erley
C M
CM
Universität Tübingen, Medizinische Klinik, Germany.
Grau
C
C
Furian
T C
TC
Wolf
S
S
Braun
N
N
Risler
T
T
D000328:Adult; D000419:Albuminuria / Q000503:physiopathology*; D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology* / Q000652:urine; D008297:Male; D012079:Renal Circulation / Q000187:drug effects*
D000959:Antihypertensive Agents; D000804:Angiotensin II