TIME RELATIONSHIPS BETWEEN PORTAL-HYPERTE NSION, DECREASE IN SODIUM-EXCRETION, AND ACTIVATION OF THE RENIN-ANGIOTENSIN SYSTEM IN RATS WITH EXPERIMENTAL BILIARY-CIRRHOSIS
Jl. Poo et al., TIME RELATIONSHIPS BETWEEN PORTAL-HYPERTE NSION, DECREASE IN SODIUM-EXCRETION, AND ACTIVATION OF THE RENIN-ANGIOTENSIN SYSTEM IN RATS WITH EXPERIMENTAL BILIARY-CIRRHOSIS, Revista de Investigacion Clinica, 49(1), 1997, pp. 15-23
1) To evaluate the biochemical, renal, histological and splanchnic and
systemic hemodynamic abnormalities induced by bile duct obstruction i
n rats, and 2) to study the temporal relationships between the start o
f portal hypertension, decrease of urinary sodium excretion and activa
tion of the renin-angiotensin system. Methods. Bile duct obstruction w
as induced in 127 male Wistar rats, and renal function, hemodynamic bi
ochemical and liver histology were evaluated at weeks 1, 2, 3 and 4 af
ter complete bile duct obstruction; the data were compared to that in
30 control rats. Results. Portal pressure significantly increased at w
eek 1 (11.7 +/- 1.5. vs. 7.8 +/- 1.5 mmHg, p < 0.05) while the mean ar
terial pressure remained stable until week 4 when a slight decrease wa
s observed (91.3 +/- 6.6 vs. 96.1 +/- 8.6 mmHg in control rats). A sig
nificant decrease in urinary sodium excretion was observed at week 1 (
1.1 +/- 0.5 mEq/24 h) compared to control rats (2.3 +/- 0.6 mEq/24 h).
In addition, hyperreninemia was observed at week 1 (5.1 +/- 0.2 vs. 2
.4 +/- 1.3 ng Ang I/mL/h, p < 0.05) and hyperaldosteronism at week 2 (
103 +/- 46 vs. 211 +/- 8.8 ng/24 h, p < 0.05) compared to control rats
. Conclusion. A temporal relationship between the begining of portal h
ypertension and a decrease of renal sodium excretion, hyperreninemia a
nd hyperaldosteronism was observed in bile duct ligated rats. This exp
erimental model could be used to evaluate the effects of new drugs to
prevent biliary cirrhosis including the abnormalities in the renal han
dling of sodium.