Peritoneal macrophages of guinea pig possibly lack LTC4 synthetase.

Peritoneal cells and adherent cells of mice and rats synthesized LTC4 and LTB4 when stimulated with A23187 in vitro. On the other hand, neither peritoneal cells nor adherent cells of guinea pigs generated LTC4, D4, and E4, but did the lower amounts of LTB4. Only generation of LTB4 was potentiated by simultaneous addition of 10 microM A.A. in this species. Enzyme solutions which were extracted from peritoneal cells of these three species were capable of converting DNCB to a colored product in the presence of glutathione and then these potencies were in the following order; guinea pig greater than mouse greater than rat. On the other hand, the potencies of converting LTA4 to LTC4 in the presence of glutathione were in the following order; mouse greater than rat much greater than guinea pig approximately equal to 0. These results suggest that macrophages of guinea pigs lack "LTC4 synthetase" and also this enzyme is different from usual GSH S-transferases.