Estriol enhances lipopolysaccharide-induced increases in nitric oxide production by Kupffer cells via mechanisms dependent on endotoxin.
BACKGROUND
Estriol causes sensitization of Kupffer cells to lipopolysaccharide (LPS) via mechanisms dependent on gut-derived LPS. Accordingly, this study examines the effect of estriol treatment on nitric oxide (NO) production from Kupffer cells.


METHODS
Rats were given estriol (20 mg/kg body weight) intraperitoneally, and Kupffer cells were isolated 24 hr later. Some rats were treated for 4 days with 150 mg/kg/day of polymyxin B and 450 mg/kg/day of neomycin to prevent growth of intestinal bacteria, the primary source of endotoxin in the gastrointestinal tract. After addition of LPS, NO production by Kupffer cell was detected using a fluorescence indicator, DAF-2.


RESULTS
Twenty-four hours after estriol administration, LPS-induced NO production by Kupffer cells was enhanced as compared with control Kupffer cells. Sterilization of the gut with antibiotics blocked this enhancement.


CONCLUSIONS
Estriol treatment in vivo enhances LPS-induced NO production in Kupffer cells.
Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan.
Nobuyuki
N
Enomoto
Yoshiyuki
Y
Takei
Tsuneo
T
Kitamura
Miyoko
M
Hirose
Kenichi
K
Ikejima
Nobuhiro
N
Sato
D000818:Animals; D001419:Bacteria / Q000187:drug effects / Q000276:immunology; D004964:Estriol / Q000494:pharmacology*; D005260:Female; D007422:Intestines / Q000382:microbiology; D007728:Kupffer Cells / Q000187:drug effects* / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology*; D008856:Microscopy, Fluorescence; D009355:Neomycin / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D011112:Polymyxin B / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D008070:Lipopolysaccharides; D009569:Nitric Oxide; D004964:Estriol; D009355:Neomycin; D011112:Polymyxin B