Angiotensinogen genotype affects renal and adrenal responses to angiotensin II in essential hypertension.
BACKGROUND
Renovascular and adrenal responses to infused angiotensin II (Ang II) are intermediate phenotypes that may indirectly reflect tissue renin-angiotensin system activity. We examine herein angiotensinogen (AGT) as a candidate gene to help elucidate potential mechanisms for previously reported AGT linkage and association studies.


RESULTS
Renal plasma flow and plasma aldosterone were measured before and after a 45-minute infusion of Ang II (3 ng x kg(-1) x min(-1)) in 190 hypertensive patients who were on carefully controlled high- and low-salt diets. Reduced renal vascular (P=0.0002) and adrenal (P=0.002) responses to infused exogenous Ang II were associated with the AGT -6A allele. In multiple logistic regression, greater body mass index, lower basal renal plasma flow, and higher diastolic blood pressure together with AGT -6A genotype were associated with lower renal vascular response. In contrast, only male sex and AGT -6A genotype were associated with lower adrenal response. When both the renal and adrenal responses to Ang II were in the lowest tertile, the AGT -6AA genotype was present in 55.6%; in contrast, when both responses were in the upper 2 tertiles, the -6AA genotype was present in only 17.8% (P=0.001).


CONCLUSIONS
A clear association between AGT genotype and response to infused Ang II was demonstrated for both the renal vasculature and the adrenal, consistent with the hypothesis that the AGT -6A genotype results in increased tissue expression of angiotensinogen and Ang II.
Hopkins
Paul N
PN
Cardiovascular Genetics, Cardiology Division, University of Utah, Salt Lake City, UT, USA. paul@ucvg.med.utah.edu
Hunt
Steven C
SC
Jeunemaitre
Xavier
X
Smith
Barbara
B
Solorio
Daniel
D
Fisher
Naomi D L
ND
Hollenberg
Norman K
NK
Williams
Gordon H
GH
D000293:Adolescent; D000311:Adrenal Glands / Q000187:drug effects; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000494:pharmacology*; D000808:Angiotensinogen / Q000235:genetics*; D000959:Antihypertensive Agents / Q000494:pharmacology*; D005260:Female; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy / Q000235:genetics*; D007668:Kidney / Q000098:blood supply / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D017595:Renal Plasma Flow / Q000187:drug effects
D000959:Antihypertensive Agents; D000808:Angiotensinogen; D000804:Angiotensin II; D000450:Aldosterone