Salt sensitivity in hypertensive rats with angiotensin II administration.
We examined the salt sensitivity of blood pressure in angiotensin II (ANG II)-induced hypertension. Wistar rats, salt loaded (0.66, 2, or 8% salt-containing diet) for 4 or 12 days, were infused intravenously with 15 or 60 ng/min of ANG II. Systolic blood pressure (SBP) was not increased by long-term (12 days) salt loading, and SBP was unchanged with ANG II and normal-salt (0.66%) diet. However, when combined with salt loading, ANG II produced hypertension in a dose-dependent fashion; compared with control (120 +/- 2 mmHg), SBP was increased with 15 ng/min of ANG II and 8% salt diet (145 +/- 5 mmHg, P less than 0.05) and with 60 ng/min of ANG II and either 2 or 8% salt diet (149 +/- 8 and 174 +/- 8 mmHg, P less than 0.05, respectively). Na space (exchangeable Na) was increased in a roughly similar pattern and correlated significantly (r = 0.531, P less than 0.05) with SBP. However, with 15 ng/min of ANG II, Na space was not different among rats on either level of salt loading, although the 8% salt diet elevated SBP. Data obtained with short-term (4 days) treatment indicate that an elevated Na space preceded development of hypertension. With 15 ng/min of ANG II and 8% salt diet for 4 days, Na space was markedly (P less than 0.05) increased, but SBP was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
Ando
K
K
Department of Internal Medicine, University of Tsukuba, Ibaraki, Japan.
Sato
Y
Y
Fujita
T
T
D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013599:Systole
D000804:Angiotensin II; D012965:Sodium Chloride; D000450:Aldosterone; D012964:Sodium