-transparent.png){kind=logo}
BACKGROUND Administration of endotoxin to rodents produces widespread tissue induction of nitric oxide synthase (NOS). To understand the mechanisms of the resulting endotoxin shock, it is important to know the cellular distribution of the inducible NOS (iNOS). METHODS We have investigated the localization and time course of expression of iNOS in rats at time 0 (control) and 3, 6, 9, and 24 hours after administration of endotoxin and also in endotoxin- and cytokine-stimulated RAW 264 murine macrophage and A7r5 aortic smooth muscle cells. We have used a rabbit antiserum to a synthetic peptide selected from the deduced sequence of the cloned macrophage enzyme (residues 47-71) and immunochemical techniques. RESULTS The antiserum reacted with an approximately 130-kilodalton protein (the molecular weight of iNOS) in Western blots of total cytoplasmic proteins from livers of endotoxin-treated rats, RAW 264 murine macrophages stimulated with endotoxin and combinations of cytokines, and purified liver iNOS, but not in control, untreated tissues. Strong cytoplasmic immunostaining was seen in RAW 264 murine macrophages and A7r5 rat aortic smooth muscle cells after stimulation, but not in nonstimulated cells. Three hours after endotoxin treatment in rats, iNOS immunoreactivity was detectable in many tissues and was at its strongest at 6 and 9 hours after stimulation. Staining was detected predominantly in macrophages distributed abundantly in heart, lung, liver, and kidney. It was also present in Kupffer cells and hepatocytes, biliary epithelium, mesangial cells, airway epithelium, and nerves supplying mesenteric blood vessels but was not detected in any vasculature. By 24 hours there was a reduction in the number of cells stained compared with that seen at 6 and 9 hours. In addition, at 24 hours after endotoxin treatment, granulomatous lesions showing iNOS staining were evident, particularly in the liver. CONCLUSIONS Antiserum raised to macrophage NOS recognizes an inducible enzyme in a wide variety of cells. Macrophages are the major site of iNOS expression in endotoxin-treated rats and show greatest staining between 6 and 9 hours after treatment. Although staining was not seen in vascular cells in vivo, levels of the enzyme that are below the immunocytochemistry detection limit cannot be excluded.
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
May 1995,
European journal of pharmacology,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
September 1997,
Anesthesiology,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
May 1996,
Investigative ophthalmology & visual science,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
April 2007,
Clinical and experimental pharmacology & physiology,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
July 2002,
Hepatology (Baltimore, Md.),
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
April 2012,
The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
October 1997,
Gastroenterology,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
May 2005,
Journal of cardiovascular pharmacology,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
January 2013,
Transplantation proceedings,
L D Buttery, and
T J Evans, and
D R Springall, and
A Carpenter, and
J Cohen, and
J M Polak
January 1999,
Journal of biomedical science,
