Regional blood flow in dahl-iwai salt sensitive rats and the effects of dietary l-arginine supplementation. Tomohiro, Atsufumi, Shoji Kimura, Hong He, Yoshihide Fujisawa, Akira Nishiyama, Kayo Kiyomoto, Yasuharu Aki, Toshiaki Tamaki, and Youichi Abe. Department of Pharmacology and Central Research Equipment Center, Kagawa Medical School, Kagawa 761-07, Japan
APStracts 3:0340R, 1996.
The purpose of the present study was to determine 1) whether different organs undergo similar increase in vascular resistance in Dahl-Iwai salt-sensitive(S) rats, and 2) the effects of chronic oral L-arginine supplementation on the regional hemodynamics in S rats. Male 6 week old S rats and salt-resistant(R) rats were maintained on an 8% NaCl chow for 4 weeks. One group(S or R rats) was maintained on tap water and the other group(S/Arg or R/arg rats) received tap water containing L-arginine at a concentration of 1.5%. Organ blood flow and cardiac output were measured with microspheres in the conscious condition. Mean blood pressure in S, S/Arg, R and R/arg rats was 159+/-5, 138+/-3, 111+/-4 and 112+/-4 mmHg, respectively. Urinary excretion of protein and albumin in S/Arg rats was significantly suppressed when compared to S rats. Concerning regional hemodynamics, the flow rate of the kidney was lower in S rats than in R rats, but there were no differences between S and R rats in the flow rates of the brain, heart, lung, liver, spleen, intestine, skeletal muscle and skin. Thus, the renal blood flow was solely reduced in S rats on a high salt diet. The flow rate of the kidney in S/Arg rats was maintained at a higher level as compared to that of S rats. L -arginine treatment tended to produce a recovery in the urinary excretion of cyclic GMP in S rats, but had no effect in R rats. Thus, the supplementation of L-arginine prevented the increase in blood pressure in S rats on a high salt diet and normalized the abnormality of renal hemodynamics accompanying salt-induced hypertension. 

Received 2 January 1996; accepted in final form 4 September 1996.
APS Manuscript Number R2-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996