Effect of ADA on fMLP- and MSU-crystals–induced PLD activity.

Neutrophils labeled with 1-O-[³H]alkyl-2-lysophosphatidylcholine were prewarmed at 37°C for 5 minutes. (A) The cell suspensions were pretreated with 10 μmol/L CB and incubated for an additional 5 minutes in the absence or presence of 0.1 U/mL ADA. Cells were stimulated with 0.1 μmol/L fMLP in the presence of 1% ethanol for 10 minutes. The amount of radioactivity incorporated into PEt was measured as described in “Materials and Methods.” The levels of [³H]PEt formed are expressed as the percentage of the radioactivity in the total lipid extracts. The data are the means ± SEM of 6 separate experiments. (B) Cell suspensions were stimulated with 3 mg/mL MSU crystals in the presence of 1% ethanol for 15 minutes, without CB. The data are the means ± SEM of 4 separate experiments.