Distribution of 3-Hydroxy Fatty Acids in Tissues after Intraperitoneal Injection of Endotoxin

to 18-carbon chain lengths are constituents of the endo-toxin [lipopolysaccharide (LPS)] of gram-negative bac-teria. We investigated whether these FAs may be used as chemical markers in measuring endotoxin concentra-tions in mammalian tissue samples. Methods: We used gas-liquid chromatography–tandem mass spectrometry to measure 3-OH FAs in serum and tissues (heart, liver, and skeletal muscles) of rats after intraperitoneal injection of Escherichia coli LPS. One group of rats (group I) received a single LPS dose of 20 mg/kg of body weight; group II rats received the same total dose but over the course of 10 days (2 mg/kg each day). Rats receiving saline (group III) were used as controls. Results: 3-OH FAs with chain lengths of 10, 12, 14, 16