FIG. 3.

LPS injection enhances prostanoid production in the thymus. Wild-type C57BL/6 mice received a single i.p. injection of 50 μg of LPS (n = 3) or a similar volume of PBS control (n = 3), and their thymuses were harvested 24 h later. The levels of PGE₂ (a) and TXB₂ (b) in thymic homogenates were determined by RIA and were adjusted for the protein concentration in the sample. LPS injection caused a doubling of the basal level of prostanoid production. To determine whether this enhanced prostanoid production could be blocked by COX inhibitors, some animals received indomethacin (n = 3) or rofecoxib (n = 3) in the drinking water starting 24 h before the injection. At the doses used, both drugs were capable of reducing prostanoid production back to baseline levels (P was not significant for the comparisons between LPS-injected mice treated with indomethacin or rofecoxib and the PBS-injected controls). Each bar represents the mean (±SEM) of six measurements (two measurements per mouse).