Enhanced superoxide anion generation but reduced leukotriene B4 productivity in thioglycollate-elicited peritoneal macrophages.
Lipoxygenase metabolism of arachidonic acid was compared between peritoneal macrophages from untreated rats and those from rats on day 7 after intraperitoneal injection of thioglycollate broth (TG). Resident macrophages (M phi) from untreated rats produced mainly LTB4 (303 +/- 25 pmol/5 x 10(6) cells) and 5-HETE (431 +/- 56 pmol/5 x 10(6) cells) when stimulated with 5 micrograms/ml calcium ionophore A23187 for 20 min at 37 degrees C. On the other hand, TG-elicited M phi generated less amounts of lipoxygenase metabolites (157 +/- 10 pmol LTB4 and 319 +/- 19 pmol 5-HETE/5 x 10(6) cells) with the same stimulus. Then, leukotriene productivity was examined by using subcellular fractions of each M phi lysate and an unstable epoxide intermediate, leukotriene A4. LTA4 hydrolase activity was mainly contained in soluble fractions from the both groups of M phi. The cytosol fraction from the resident M phi exhibited the following specific and total activity; 2.2 +/- 0.1 nmol LTB4/mg protein/5 min and 12.2 +/- 0.5 nmol LTB4/5 min per 10(8) cells. On the contrary, the cytosol fraction from the TG-elicited M phi showed 1.9 +/- 0.1 nmol LTB4/mg protein/5 min and 9.6 +/- 0.3 nmol LTB4/5 min per 10(8) cells. The resident M phi, however, generated 0.14 +/- 0.04 nmol O2-/min/4 x 10(5) cells whereas the TG-elicited M phi did 0.49 +/- 0.13 nmol O2-/min/4 x 10(5) cells when stimulated with wheat germ lectin. These results suggest that the TG-elicited macrophages show enhanced superoxide production but generate less lipoxygenase metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)
Abe
M
M
Research Institute for Disease of the Chest, Medical School, Kyushu University, Fukuoka, Japan.
Takahashi
H
H
Gouya
T
T
Nagata
N
N
Shigematsu
N
N
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004851:Epoxide Hydrolases / Q000378:metabolism; D007975:Leukotriene B4 / Q000096:biosynthesis*; D008084:Lipoxygenase / Q000096:biosynthesis; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D010529:Peritoneal Cavity; D051381:Rats; D011919:Rats, Inbred Strains; D013481:Superoxides / Q000378:metabolism*; D013864:Thioglycolates / Q000494:pharmacology*
D013864:Thioglycolates; D013481:Superoxides; D007975:Leukotriene B4; D008084:Lipoxygenase; D004851:Epoxide Hydrolases; C043134:leukotriene A4 hydrolase