Endothelial, but not the inducible, nitric oxide synthase is detectable in normal and portal hypertensive rats.
BACKGROUND
Chronic portal hypertension is accompanied by a nitric oxide (NO) dependent vasodilation. Three isoforms of NO producing synthases (NOS) are characterized: neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). Sources of increased NO levels in chronic hypertension is disputed.


METHODS
To determine eNOS and iNOS expression in different organs of portal hypertensive and control rats, we divided Sprague-Dawley rats in 6 groups: (1). Partial portal vein ligated rats, (2). Bile duct ligated rats, (3). Carbon tetrachloride treated rats, (4). Sham operated rats, (5). Untreated control rats, and (6). LPS treated rats. Immunohistochemistry (IHC) and immunoblotting (IB) using antibodies against eNOS or iNOS were carried out on samples from thymus, aorta, heart, lung, oesophagus, liver, spleen, kidney, pancreas, small and large intestine.


RESULTS
IHC revealed an even eNOS expression in all groups. Expression of iNOS was restricted to macrophages in organs of LPS treated and the thymus of rats. IB mirrored these results.


CONCLUSIONS
In chronic portal hypertension, the main source for NO production depends on eNOS activity.
Stumm
Michael Martin
MM
Department of Research, University Hospital Basel, 4031-Basel, Switzerland. michael.stumm@unibas.ch
D'Orazio
Daniel
D
Sumanovski
Lazar Trajan
LT
Martin
Pierre-Yves
PY
Reichen
Juerg
J
Sieber
Cornel Christian
CC
D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D019084:Fluorescent Antibody Technique, Indirect; D006975:Hypertension, Portal / Q000201:enzymology* / Q000209:etiology; D007124:Immunoenzyme Techniques; D008106:Liver Cirrhosis, Experimental / Q000150:complications / Q000201:enzymology*; D008264:Macrophages / Q000201:enzymology; D008297:Male; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017207:Rats, Sprague-Dawley; D013950:Thymus Gland / Q000201:enzymology
D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat