Intravenous endotoxin does not increase tissue extravasation of albumin in rats.
BACKGROUND
It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.


METHODS
Chloralose anaesthetised male Wistar rats received E. coli lipopolysaccharide (LPS), 3 mg kg-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.


RESULTS
LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n = 8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n = 8). In the 5-h LPS rats, clearance was lowered (n = 8) in the entire gastrointestinal tract and in testes, compared to controls (n = 8). The serum nitrite/nitrate concentration was higher in animals given LPS (n = 6) than in controls (n = 6).


CONCLUSIONS
After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.
Department of Anaesthesiology and Intensive Care, University Hospital, Linköping, Sweden.
K
K
Metcalf
T
T
Sundqvist
B
B
Lisander
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002199:Capillary Permeability / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D007275:Injections, Intravenous; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000633:toxicity*; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D010953:Plasma Volume / Q000187:drug effects / Q000502:physiology; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D018805:Sepsis / Q000139:chemically induced / Q000378:metabolism; D012709:Serum Albumin / Q000378:metabolism*; D012711:Serum Albumin, Radio-Iodinated / Q000493:pharmacokinetics; D014018:Tissue Distribution
D008070:Lipopolysaccharides; D019275:Radiopharmaceuticals; D012709:Serum Albumin; D012711:Serum Albumin, Radio-Iodinated; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat